A child’s health and well-being are fostered by a home environment with engaged and skillful parenting that models, values, and encourages sensible eating habits and a physically active lifestyle. By promoting certain values and attitudes, by rewarding or reinforcing specific behaviors, and by serving as role models, parents can have a profound influence on their children. It is not surprising, therefore, that sedentary behaviors, obesity, and other chronic disease risk factors tend to cluster within families. Although some of these risk factors may have a genetic component, most have strong behavioral aspects. The family is thus an appropriate and important target for interventions designed to prevent obesity in children through increasing physical activity levels and promoting healthful eating behaviors.
In the United States in the 21st century, there are a great many pressures on parents and children that can adversely affect daily family life. For example, with the frequent need for both parents to work long hours, it has become more difficult for many parents to play with or monitor their children and to prepare home-cooked meals for them. Of two-parent households, 62.4 percent have both parents in the labor force; in one-parent homes, 77.1 percent of the mothers and 88.7 percent of fathers are working (Fields, 2003). Because the school day is shorter than the work day, many children come home to an empty house, where they may be unsupervised for several hours (Smith, 2002). In a national survey, parents report being well aware of the need to spend more time with their children but believe they do not have such time available (Hewlett and West, 1998). Parents
from diverse socioeconomic categories actually cite a “parental time famine”—insufficient time to spend with their children. Economic and time constraints, as well as the stresses and challenges of daily living, may make healthful eating and increased physical activity a difficult reality on a day-to-day basis for many families (Devine et al., 2003).
The committee has adopted an ecological framework that considers children and youth as being influenced primarily by the family, particularly in the younger years, though other micro-environments—including the neighborhood, workplace, and school—also have important impacts on parenting and on individual and family functioning (see Chapter 3). In this ecological framework, parenting is influenced by the larger (macro) economic, political, social, and physical environments, as well as by socioeconomic status, parental goals, personal resources, and child characteristics (Parke and Buriel, 1998). Cultural norms are also an important factor. For example, parents may feel pressured to contribute cookies or soft drinks to the classroom or child-care setting if the other children are bringing in similar foods and beverages. On the other hand, if new values about what constitutes appropriate food choices for children become normative, this can produce positive changes in individual families and in their children’s daytime environments.
The ecological perspective leads to strategies that target parents directly, as well as to other strategies designed to influence contextual factors that might otherwise serve to undermine healthful family values and practices. Therefore, a number of the committee’s recommendations focus on promoting changes in nonhome settings (e.g., schools, communities, the built environment, the media) in order to support parents in their efforts to serve as positive models for children’s eating and physical activity and to allow them to provide children with appropriate environments for preventing obesity. This is particularly important for families from high-risk populations who live in conditions that are not supportive of healthful lifestyles.
From a practical standpoint, parents play a fundamental role as household policy makers. They make daily decisions on recreational opportunities, food availability at home, and children’s allowances; they determine the setting for foods eaten in the home; and they implement countless other rules and policies that influence the extent to which various members of the family engage in healthful eating and physical activity.
The committee acknowledges the broad and diverse nature of families in the United States. According to a recent U.S. Census Bureau report, in 2002 there were more than 72 million children (under 18 years of age) in the United States (Fields, 2003). Approximately 69 percent of them lived with two parents, 23 percent lived with only their mother, approximately 5 percent lived with their father, and 4 percent lived with other family members, usually grandparents, or in other situations (Fields, 2003). This report
uses the term “parents” in its broadest sense to incorporate all those who are primary caregivers to children in the home.
Although treatment of childhood obesity is beyond the scope of this report, treatment studies have demonstrated that intensive involvement of parents in interventions to change obese children’s dietary and physical activity behaviors has contributed to success in weight loss and long-term weight maintenance (Coates et al., 1982; Kirschenbaum et al., 1984; Epstein et al., 1990, 1994; Golan et al., 1998; Golan and Crow, 2004). It is plausible that family-based strategies that prevent weight re-gain in these studies are likely to be informative in the prevention of obesity. The fundamental influence of parents on the eating behavior of their children has also been demonstrated in the prevention of eating disorders (Graber and Brooks-Gunn, 1996). Finally, a 10-year longitudinal study conducted in Denmark has identified parental neglect as a powerful predictor of the subsequent development of obesity (as compared to putative biological predictors such as obesity in one or both parents) (Lissau and Sorensen, 1994).
While the home is an influential setting, it is also the least accessible for health promotion efforts. Mechanisms for parent education are varied and many provide only brief opportunities for health-care professionals, teachers, or others to interact with parents and share information and resources. As discussed throughout the report, there are resources in the school and the broader community that can support and inform parents and caregivers, children, and youth (see Chapters 6 and 7).
In the remainder of this chapter, the committee explores some of the ways in which parents and families can encourage healthful eating behaviors and increased physical activity. This report is not the place for an exhaustive discussion of diet and physical activity, nor is it meant to be the definitive source for parental advice; rather, the committee sought to present some actionable steps that can be taken by parents, families, children, and youth. It is important to note that many families are already quite physically active and put time and effort into providing healthful meals. It is important that parents and children extend these efforts and priorities to their schools, neighborhoods, and communities (Chapters 6 and 7) and become involved in ensuring that opportunities are made available and expanded for all families.
PROMOTING HEALTHFUL EATING BEHAVIORS
For decades, scientists have suggested that there are critical periods in the brain development of animals and humans that may profoundly affect food intake and body weight (in particular, body fat) beginning in utero—when many of the systems that regulate food intake and body weight initially develop. The factors that influence the quantity and quality of the
maternal diet at the time of conception and throughout pregnancy—some of which may be within the control of the mother, while others result from social and economic environments—are thus important to consider. A recent study of 8,494 low-income children found that maternal obesity in the first trimester of pregnancy more than doubled the risk of the child being obese at 2 to 4 years of age (Whitaker, 2004). Furthermore, there are concerns that the offspring of mothers with gestational diabetes mellitus may be at higher risk for obesity, but the results are inconsistent (Silverman et al., 1998; Whitaker et al., 1998; Gillman et al., 2003). Needless to say, women of child-bearing years should pursue a healthful lifestyle that emphasizes sound dietary and physical activity habits, and because of the importance of a healthy maternal body weight at conception and adequate weight gain during pregnancy, these goals should be embraced and nurtured by the entire family.
Researchers are examining early determinants of obesity, including factors during infancy; however, much remains to be learned. Issues being explored include the combined effects of low birthweight followed by rapid weight gain during early infancy (Stettler et al., 2002, 2003).
The associations between various feeding methods during infancy and childhood obesity have been the most thoroughly explored. Epidemiological data suggest that breastfeeding, even as it is generally practiced in the United States—that is, as a nonexclusive source of nutrition, usually of short duration—confers a small but significant degree of protection from childhood obesity, although it is not certain why this is so or the extent to which other factors may confound this finding. A recent review of 11 epidemiologic studies with adequate sample size1 found that eight of the studies showed breastfed children to be at a lower risk of overweight after controlling for potential confounders (Dewey, 2003). Studies published since that review have generally confirmed that finding but not in all subpopulations. For example, Bergmann and colleagues (2003) examined the weight status of a cohort of children at 6 years of age and found that those who were bottle fed as infants had a higher prevalence of obesity than those who were breastfed. Other risk factors for adiposity at 6 years of age
included overweight of the mother, maternal smoking during pregnancy, and low social status. In research on the weight status of 12,587 children in the United States at 4 years of age, Grummer-Strawn and Mei (2004) found that greater duration of breastfeeding showed a protective effect on the risk of overweight among non-Hispanic whites, but not among non-Hispanic blacks or Hispanics. The reasons for differences among ethnic groups are not clear; the study did not examine supplementation by formula or foods or varying dietary or physical activity patterns. A study by Bogen and colleagues (2004) also found no association between breastfeeding and obesity among 20,518 low-income black children (the study sample did not include Hispanics).
Breastfeeding is thought to promote the infant’s ability to regulate energy intake, allowing him or her to eat in response to internal hunger and satiety cues—that is, to assume greater control in determining meal size (Fisher et al., 2000). In contrast, a caregiver who is formula feeding an infant may use visual information about how much remains in the bottle to “encourage” the infant to finish the bottle, potentially fostering overfeeding. Even if the caregiver makes no such effort, the uniform composition of formula, both during a single feeding and over the duration of infancy, may not provide the infant with the same metabolic/hormonal cues that are supplied with breast milk. Because the composition of breast milk changes during each feed and from one feeding to the next over the course of lactation, the full effects of this variation are not experienced when breastfeeding is nonexclusive or of short duration (Lederman et al., 2004).
Factors in breast milk may elicit metabolic programming effects that contribute to the protective association between breastfeeding and childhood obesity. There is the possibility that other parental lifestyle factors and behaviors, not yet identified, may undermine or overwhelm that protection (Dewey, 2003). Lifestyle and cultural factors may also explain the discrepant findings among different ethnic groups. It is worth emphasizing that a protective effect of breastfeeding was found in the majority of studies reviewed although not in all. But in none of the 11 studies reviewed by Dewey (2003) or those published since that review has breastfeeding been associated with increased risk for childhood obesity; breastfeeding was found to be either protective or neutral. None of the studies have found formula feeding to be protective against childhood obesity.
Research indicates that many flavors from the mother’s diet are transmitted to her breast milk (Mennella and Beauchamp, 1991; Mennella, 1995). By the time complementary foods are introduced, therefore, the breastfed infant has already had experience with a variety of flavors from the adult diet, which may promote acceptance of foods during weaning (Sullivan and Birch, 1994; Mennella et al., 2001; Lederman et al., 2004). Experience with numerous flavors in breast milk (as opposed to the lack of
variety experienced by the formula-fed infant) may also have more general effects, promoting the infant’s acceptance of a wide range of new foods as he or she matures; further research is needed in this area (Mennella and Beauchamp, 1998; Lederman et al., 2004).
Much remains to be learned about the extent of the association between breastfeeding and childhood obesity. Nonetheless, breastfeeding is likely to be at least weakly protective against obesity, and despite the fact that the protective effects may be overwhelmed by events and environmental factors that occur later in childhood, there are numerous ancillary benefits of breastfeeding (AAP, 2004). Breastfeeding is recommended for all infants. Exclusive breastfeeding is recommended for the first 4 to 6 months of life and breastfeeding, along with the age-appropriate introduction of complementary foods, is encouraged for the first year of life. This is in accordance with the American Academy of Pediatrics (2004) statement recommending breastfeeding and stating that in developed countries “complementary foods may be introduced between 4 and 6 months” and the World Health Organization (2003) recommendation that encourages exclusive breastfeeding for the first 6 months of life, to the extent that this is practical for the mother and family.
Another issue that is discussed regarding infant feeding is serving size—ensuring that infants receive the appropriate amounts of milk or foods. Research has shown that early in life, infants are responsive to the energy density of food and are capable of controlling the volume taken during a feeding. Thus, even by about 6 weeks of age, infants can adjust the volume of formula consumed based on the energy density of the formula, so that total energy intake remains relatively constant (Fomon et al., 1975). Nonetheless, there is the possibility that infants can be coaxed to eat beyond satiety and that has been postulated by several researchers as a potential contributor to childhood obesity (Bergmann et al., 2003; Dewey, 2003; Lederman et al., 2004). Concern has been expressed that precocious introduction of sweetened beverages and high-fat/sweet-tasting foods may be important contributors to childhood obesity by possibly developing early preferences for such foods and beverages (Fox et al., 2004; Lederman et al., 2004). Documentation that such concerns are well founded are the findings from the Feeding Infants and Toddlers Study (FITS) that soft drinks and French fries are being fed to infants as young as 7 months of age (Fox et al., 2004).
Toddlers and Young Children
Children tend to avoid new foods. But during the transition from the exclusive milk diet of infancy to consuming a varied, modified adult diet, virtually all foods are new to the child. Fortunately, it has been found that
if children have opportunities to try new foods without being coerced to eat them, many of these foods, even if initially rejected, will become part of their diet (Birch and Marlin, 1982; Loewen and Pliner, 1999). Such early experience with new options will be especially important in learning to accept fruits, vegetables, and other nutrient-rich foods later on in life (Birch, 1999; Skinner et al., 2002).
Food flavor preferences are powerful determinants of intake for children. Because infants are predisposed to prefer sweet and salty tastes, they tend to readily accept foods that are sweet or salty (Cowart, 1981; Beauchamp and Cowart, 1985; Mennella and Beauchamp, 1998). In contrast, preferences for foods that lack such tastes are learned, requiring repeated positive experiences.
Initial rejection of new foods is expected and normal. As many as five to ten exposures may be needed before certain new foods are accepted, and repeated experience is most critical during the first few years of life. Recent findings reveal that parent-led exposure can increase children’s acceptance of vegetables (Wardle et al., 2003; Lederman et al., 2004), and that childcare and preschool settings are also effective locations for promoting children’s acceptance of new foods (Nicklas et al., 2001). Research also shows that increasing the school-based availability and accessibility of fruits and vegetables in particular can promote children’s intake, at school as well as at home (Baranowski et al., 2000; Weber Cullen et al., 2000).
Of course, children can be equally responsive to less healthful options when made available. Because their preferences for high-fat, energy-dense foods are, in part, learned, providing children with frequent exposure to such foods may reinforce their liking for them (Johnson SL et al., 1991). In the 2002 FITS, which examined the dietary intake of 3,022 infants and toddlers, parents reported that 23 percent of infants and 33 percent of toddlers had not consumed any fruit during the preceding 24 hours; similarly 18 percent and 33 percent of infants and toddlers, respectively, had not consumed any vegetables (Fox et al., 2004). This study also reported changes in intake from 4 to 8 months of age when deep yellow vegetables (e.g., carrots, sweet potatoes, squash) were the vegetables consumed most often, to the patterns at 15 to 18 months, when French fries or other fried potatoes were the predominant vegetables (Fox et al., 2004). Parents should promote healthful food choices among toddlers and young children by making a variety of nutritious, low-energy-dense foods, such as fruits and vegetables, available to them. Encouraging toddlers and young children to try a variety of foods, including fruits and vegetables, often involves offering new foods multiple times.
Beyond quality is the issue of quantity. Limited empirical evidence suggests that children, especially those in the toddler years, have a physiological sense of satiety that guides them to eat only until they are full.
McConahy and colleagues (2002) found that the food portion sizes consumed by children 1 to 2 years of age have been consistent over the past 20 years. However, as children develop, they become increasingly responsive to environmental cues such as portion size; by the age of 5 years, larger portions can lead to increased food intake (Rolls et al., 2000). This issue is discussed further below.
Older Children and Youth
As children develop, they play an expanding role in determining the foods that are available to them. They make their own choices at school and in other out-of-home settings, and they increasingly influence family food purchases. Furthermore, as they begin to be influenced by their peers and the broader culture, they may make certain food choices based on popular appeal. It is also important to note, however, that parents are important role models and their dietary intake influences that of their children (see section below on role models).
Food and Beverage Selection and Availability
Parents can promote wise food selections and a wholesome overall diet by making nutritious options available to children. Research has shown that children’s consumption of fruit, 100 percent fruit juice, and vegetables are positively influenced by the availability and accessibility of these foods in the home (Nicklas et al., 2001; Cullen et al., 2003). Similarly, parents can limit the types and quantity of energy-dense high-calorie foods (e.g., cookies, chips) that are available in the home, particularly those that have low nutrient content. Improved consumer nutrition information in restaurants and on food labels (see Chapter 5) will provide parents and young people with enhanced information on which to base their dietary decisions.
Parents are responsive to children’s attempts to influence food purchases (Galst and White, 1976). Interviews with 500 children and youth aged 8 to 17 years found that 78 percent of respondents noted that they influence family food purchases (Roper ASW, 2003). For their part, 84 percent of the parents stated that their children do indeed influence such purchases.
The Dietary Guidelines for Americans and the Food Guide Pyramid provide information on the types of foods that make up a balanced and nutritious diet (USDA and DHHS, 2000; USDA, 2004). Although it is not the purpose of this report to duplicate that information, the committee wishes to emphasize the responsibilities of children (particularly older children), youth, and parents in choosing and providing a balanced diet. Parents should promote healthful food choices by school-age children and
youth by making a variety of nutritious, low-energy-dense foods, such as fruits and vegetables, available in the home. Because nutrient quality should be a major consideration in selecting the family’s foods and beverages, parents should limit their purchases of items characterized by high caloric content and low nutrient density.
The mealtime setting has been shown to affect diet quality in children and youth. Several studies have shown that increased frequency of family dinners is positively associated with older children’s and adolescents’ consumption of fruits and vegetables, grains, and calcium-rich foods, and negatively associated with their consumption of fried food and soft drinks (Gillman et al., 2000; Neumark-Sztainer et al., 2003a). The influence of watching television during mealtime is another area for further research. Coon and colleagues (2001) found that watching television during mealtime was associated with consumption of fewer fruits and vegetables and increased consumption of soft drinks, salty snacks, pizza, and red meat.
One of the issues that has been raised regarding childhood obesity is the potential role of sweetened beverages, such as soft drinks and “flavored drinks” (not 100 percent juices). These beverages do not provide nutrients that are needed by growing children, but do increase the caloric intake. Nevertheless, soft drink consumption more than tripled among adolescent boys between 1977-1978 and 1994, rising from 7 to 22 ounces per day (Guthrie and Morton, 2000; French et al., 2003). By the time they are 14 years of age, 32 percent of adolescent girls and 52 percent of boys are consuming three or more eight-ounce servings of soft drinks daily (Gleason and Suitor, 2001). FITS reported that infants as young as 7 months of age are consuming soft drinks as well (Fox et al., 2004). There are concerns about the effect of increased soft drink consumption on reducing micronutrient intakes and increasing energy intake (IOM, 2002) and on displacing the intake of more nutrient-rich options such as milk (ADA, 2004). Milk consumption by adolescents declined 36 percent from 1965 to 1996 (Cavadini et al., 2000). An analysis of data from the 1994-1996, 1998 Continuing Survey of Food Intakes by Individuals (CSFII) found that children and adolescents (>12 years of age) drank more soft drinks than milk, 100 percent juices, or fruit drinks (Rampersaud et al., 2003).
The link between beverage consumption and body mass index (BMI) is not definitive. In an analysis of CSFII data, Forshee and Storey (2003) reported that BMI calculated from self-reported height and weight had little or no cross-sectional association with beverage consumption. In contrast, in a prospective study of middle schoolers in which height and weight were measured directly, Ludwig and colleagues (2001) reported significant positive associations between sweetened beverage consumption and increases in BMI and obesity incidence. In a recent randomized controlled trial of a 1-year classroom-based intervention focused on carbonated beverages, dental
health, and dietary intake, James and colleagues (2004) reported a significant decrease in the prevalence of overweight and obesity in the group of children receiving the intervention compared to controls. However, methodological limitations prevent conclusions regarding whether reducing soft drink consumption led to the observed changes in obesity prevalence (French et al., 2004). Further, experimental studies of the effects of reducing sweetened beverage intakes are needed to examine the potential efficacy of this approach for reducing weight gain, as well as the hypothesized causal link between sweetened beverage consumption and obesity.
Much remains to be learned about whether a unique association exists between intake of sweetened beverages and changes in BMI. Because of concerns about excessive consumption of sweetened options and the displacement of more nutrient-rich or lower calorie alternatives, children should be encouraged to avoid high-calorie, nutrient-poor beverages.
Portion Control and Eating in the Absence of Hunger
In addition to ensuring the quality of children’s diets, it is important for parents to consider the quantity of food being consumed. Researchers examining the recent increases in portion sizes have found that Americans consumed larger portion sizes of nearly one-third of 107 widely consumed foods when comparing 1989-1991 with 1994-1996 data (Nestle, 2003; Smiciklas-Wright et al., 2003).
Although long-term studies investigating the effects of portion size on weight gain are lacking, short-term studies confirm that larger portions do increase intake, especially among adults and children aged 5 years and older. In research involving a range of foods that included sandwiches, macaroni and cheese, popcorn, and cookies, the larger the portion size offered, the larger the amount consumed (reviewed by Rolls, 2003; Diliberti et al., 2004).
While evidence shows that infants and toddlers can self-regulate their energy intake (discussed earlier), a series of studies found that by the age of 5 many children eat what they are served; physiological satiety cues, if they are present, are overridden by environmental cues (such as larger portion sizes) that stimulate them to eat more, even if they are not hungry (Rolls et al., 2000). In this research, 3- to 5-year-olds were fed a standard lunch on two different days in their usual preschool setting. Lunches differed only in the portion size of the entrée. Older preschoolers responded in much the same way that adults do; when given a larger portion, they ate more. But younger children were relatively unresponsive to portion size, providing more indirect support that they are still eating primarily in response to internal signals of hunger and satiety (Rolls et al., 2000; see Rolls, 2003 for a review of the adult literature).
In subsequent research, Orlet-Fisher and colleagues (2003) explored
the effects of children’s chronic exposure to large portions. Results indicated that when served larger portions, children ate substantially more food—but giving them the opportunity to serve themselves mitigated these effects because they tended to self-select smaller portions. In one study, they consumed 25 percent less of the lunch entrée when they served themselves, as compared to other occasions when a larger portion was served to them (Orlet-Fisher et al., 2003). The portion sizes that the children self-selected and consumed were more similar to standard, recommended serving sizes than to the large portions they had been offered, suggesting that giving children control over portion size may prevent overeating or eating in the absence of hunger.
The goal for parents is to promote the normal and effective development of internal satiety cues so that children learn to rely on their own sense of fullness. However, research suggests that restricting palatable foods can lead to increased preference for these foods and that pressuring children to “clean the plate” can encourage overeating. Such practices can prompt children to attend to external cues, such as the availability of food or the amount remaining on the plate, and divert them from internal cues of hunger and satiety (Birch et al., 1987; Fisher and Birch, 1999; Orlet-Fisher et al., 2003). Golan and Crow (2004) point out the impact of parenting styles on children’s eating behaviors: “authoritative parenting (in which parents are both firm and supportive and assume a leadership role in the environmental change with appropriate granting of child’s autonomy) rather than authoritarian style (which controls child-feeding practices) was found to be the effective parental child-feeding modality” (p. 358).
Child characteristics influence the choice of these feeding practices; overweight children tend to elicit higher levels of parental restriction, and thinner children are more likely to be pressured to eat. Pressure and restriction tend to be used with different foods (pressure with perceived “healthful foods” that parents want to encourage; restriction with some snack foods that parents want to limit), but a parent who uses one tactic is likely to use the other as well (Fisher et al., 2002). However, one of the limitations of this research to date is that it has been conducted with middle-class white families and sometimes only with one gender, severely limiting the ability to generalize.
Research has also shown that using foods as rewards or in other positive contexts can result in greater preference for and intake of those foods (Birch et al., 1980; Birch, 1981). Furthermore, this practice dissociates eating from hunger. Parents should avoid using food as a reward.
More research is also needed to understand developmental progression—the neural and physiological underpinnings of hunger and satiety—and the regulation of food intake and energy balance. It is also important to learn more about how the timing of snacks and meals influence eating and weight status.
Meanwhile, research results that have been obtained thus far should prompt parents to consider making constructive family policies that move away from pressures and restrictions and more toward positive practices regarding what, where, and when foods and beverages can be consumed. Such practices, by which parents can help children learn to regulate their own energy intake, include the following:
Allow children to determine their own portions at meals.
Encourage children to pay attention to their own internal signals of fullness and permit them to decide when they have finished eating a meal. Do not insist on their “cleaning the plate.”
Avoid using food as a reward. This practice dissociates eating from hunger and clearly establishes preferences for foods used as rewards.
Make fruits and vegetables readily available in the home to encourage selection of these foods as snacks and desserts.
Offer smaller portions of foods (e.g., smaller cookies or slices of pizza).
Carefully consider the quality of and the possible need to limit the types of snack foods and beverages that are available and accessible to children in the home.
Parents should educate their children, from a young age, about making decisions regarding dietary intake, so that as they get older, the children can take on increasing responsibility for decisions regarding the types and amounts of foods and beverages they consume. While permitting children to determine portion sizes for themselves, parents should encourage smaller portions with an option for seconds. For children too young to serve themselves, parents should offer age-appropriate portion sizes.
PROMOTING PHYSICAL ACTIVITY
There is still much to be learned about the determinants of physical activity and fitness in children and adolescents and how to influence their level of activity throughout the developmental stages. As discussed throughout the report, physical activity can influence the body-fat level of children (Gutin et al., 2004).
Correlates of Physical Activity
Developmental, Biological, and Psychosocial Correlates
Children’s gender and age are both important factors to consider in examining physical activity levels. Boys are generally more involved in
moderate to vigorous physical activity than are girls (DHHS, 1996; Sallis et al., 2000). Explanations may include differential development of motor skills, body composition differences during growth, variations in socialization regarding sports and physical activity, and other social and environmental factors (Sallis et al., 1992; Kohl and Hobbs, 1998). From a developmental perspective, unstructured gross motor play is important in young children for optimal brain development and is important for social, emotional, and cognitive development (Butcher and Eaton, 1989; Pica, 1997). As children get older they are generally less physically active, although this may be more true for girls than for boys (Goran et al., 1999). The social, psychological, and behavioral effects of puberty may play an important role in physical activity levels (Lindquist et al., 1999), although more research is needed, particularly research that focuses on measured physical activity (e.g., using accelerometry) rather than self-report or other indirect methods of documenting physical activity.
The personal psychosocial factors that influence physical activity differ somewhat between children and adolescents. Intention to be physically active, preference for physical activity, positive beliefs about physical activity, enjoyment of physical activity, and enjoyment of physical education classes have been shown to be positively associated with physical activity in children (Stucky-Ropp and DiLorenzo, 1993; Pate et al., 1997; Trost et al., 1997, 1999; DiLorenzo et al., 1998; Sallis et al., 2000). Perceived barriers to physical activity (including not enough time or the activity is too hard) have been found to be negatively associated with physical activity behavior in children (Sallis et al., 2000).
In adolescents, correlates of physical activity include perceived activity competence, intention to be active, sensation seeking, perception of academic rank and academic expectations, and depression (an inverse correlate) (Sallis et al., 2000; Motl et al., 2002; Schmitz et al., 2002). Perceived self-worth, perceived time constraints, and value placed on health and appearance may influence prevalence of physical activity or change in physical activity levels in adolescent girls (Schmitz et al., 2002; Neumark-Sztainer et al., 2003b).
Physical activity self-efficacy (confidence in one’s ability to participate in exercise) has been widely studied as a potential psychosocial correlate of increased levels of physical activity, but the association is not clear in children and adolescents (CDC, 1997).
Social Environment Correlates
The social environment in which children live strongly influences their health behaviors in general and levels of physical activity in particular, and the primary social influences on young people are their family and peers. But although it is intuitively attractive to hypothesize that parents’ physical
activity behavior correlates with that of their children, research does not definitively support that hypothesis. Sallis and colleagues (2000), in a review of correlational studies, reported that parents’ physical activity had an indeterminate relationship to children’s physical activity. Kohl and Hobbs (1998), however, reported that children whose parents are physically active are much more likely than other children to be physically active.
In any case, parents’ support for a child or adolescent’s physical activity, and the perceptions of their parents’ physical activity behavior, do appear to be important correlates of physical activity in children and youth. Parental support can include a wide range of actions, from encouraging the child or adolescent to try or to continue a new activity, to providing transportation to an activity class, to purchasing sports equipment.
Researchers have identified several family variables, including support for physical activity, mother’s perception of barriers to physical activity, and parental modeling of physical activity, to be associated with physical activity levels in fifth- and sixth-grade boys and girls (Stucky-Ropp and DiLorenzo, 1993; DiLorenzo et al., 1998). Trost and colleagues (1997, 1999) found that perception of mother’s physical activity level was a correlate of vigorous physical activity in fifth-grade girls and that active sixth-grade boys were more likely than nonactive boys to report that their mothers were physically active. Other studies have also identified family support for physical activity as a correlate of children’s physical activity (Sallis et al., 2000; Zakarian et al., 1994).
Although the focus of influence in adolescence shifts from family to peers, parents and other family members continue to influence teenagers’ physical activity. In the studies reviewed by Sallis and colleagues (2000), parental support, direct help from parents in being physically active, and siblings’ physical activity were consistently correlated with adolescents’ physical activity. McGuire and colleagues (2002) found a significant, though modest, relationship between parents’ reported encouragement and physical activity levels in female adolescents of all racial and ethnic groups and in African-American and white boys. In a population of inactive adolescent girls, social support from parents, peers, and teachers was consistently and positively associated with change in physical activity over time (Neumark-Sztainer et al., 2003b). Researchers did not find a clear positive correlation between parents’ reported physical activity behaviors and those of their teenage children (McGuire et al., 2002).
Although Schmitz and colleagues (2002) found that young adolescents who received free or reduced-price lunches reported higher levels of physical activity, most studies report a positive correlation between parents’ education and socioeconomic status (SES) and children’s physical activity (Pate et al., 1996; Gordon-Larsen et al., 2000). Parents who have the time and resources to participate in physical activity themselves may be better
able to encourage their children to do likewise, and they are more apt to have the resources to enroll their children in sporting activities and provide sports equipment and the associated transport (Koivisto et al., 1994; Sallis et al., 1999). Researchers have identified other barriers faced by low-income families with regard to healthful physical activity behaviors, including a lack of safe places for physical activity (AAP, 2003).
Physical Environment Correlates
As discussed in Chapters 6 and 7 on communities and schools, there are many factors—including safety and access to physical activity opportunities—that play important roles in determining when, where, and how children engage in physical activity. One of the strongest correlates of physical activity in children is the amount of time spent outside (Klesges et al., 1990; Baranowski et al., 1993; Sallis et al., 1993). In most homes, after all, there are limited options for physical activity inside the home, and it is outdoors where children are generally more physically active and where more energy is expended.
A recent comprehensive review of physical activity interventions identified 11 studies that were family-based and met the methodological criteria of the Task Force on Community Preventive Services (Kahn et al., 2002). Most of these interventions were implemented as parts of multicomponent school-based studies such as the Child and Adolescent Trial for Cardiovascular Health (described in Chapter 7) and generally involved parent-child activities that were completed at home (Johnson CC et al., 1991; Hopper et al., 1992, 1996; Davis et al., 1995; Edmundson et al., 1996; Sallis et al., 1997; Manios et al., 1999). Four other family-based studies (Nader et al., 1983, 1989; Bishop and Donnelly, 1987; Baranowski et al., 1990) examined interventions to educate families on nutrition and physical activity through sessions at community centers or schools. The interventions that were part of a school-based program were marginally more effective in increasing physical activity or improving indicators of cardiovascular fitness, but it was not possible to differentiate the effects of the family intervention from those of the other study components. In another study, Taggart and colleagues (1986) demonstrated that a program that used parent training and family contracting increased physical activity in children with low fitness levels.
More remains to be learned about developmentally appropriate interventions to encourage physical activity, as well as about the changes in the nature and duration of physical activity throughout childhood and adoles-
cence. The development of better tools for measuring physical activity will help to eliminate some of the inconsistencies found in the data and is an important research need. It is also important to learn more about the factors during childhood and adolescence that foster lifelong habits of daily physical activity.
Promoting Physical Activity
Parents should promote physical activity by supporting and encouraging children and youth to be active and play outdoors and participate in opportunities for physical activity. This may increase the time that parents spend outdoors interacting with their children or ensuring their safety or going with their children to the park, playground, gymnasium, or other appropriate location for physical activity. The ancillary benefits of physical activity and outdoor play and interaction are numerous. For children, youth, and parents, the time spent interacting outdoors increases opportunities for social contact, nurturing, bonding, and maturational guidance. In some residential areas, where safety is such a concern that parents cannot let their children play outside the home, there is a particular need for the community to develop and foster opportunities for outside play—including parks, playgrounds, and recreational facilities (see Chapter 6).
There are numerous ways in which parents can help to increase their child’s or adolescent’s physical activity levels by supporting and engaging in a range of recreational or utilitarian (e.g., walking to the grocery store) activities that may promote lifelong habits of regular physical activity (Shape Up America, 2004). Examples include:
Walking or bicycling (with proper safety measures including helmets) to run errands or as a regular means of transport
Encouraging and monitoring outdoor play
Assessing the community for opportunities for physical activity and supporting participation by the child and family (e.g., parks, baseball fields, soccer fields, lakes, pools, gyms, community and youth programs, recreational leagues, and camps)
Engaging in family outings and vacations that are centered around physical activity
Giving gifts (e.g., jump ropes, balls, sports equipment) that encourage activity.
Not every parent has the skills to coach a child in a particular physical activity, but parents can still function as “cheerleaders” for their child and adolescent. This type of emotional support is not only meaningful and rewarding to the child but also may encourage still more physical activity.
Furthermore, parents can be effective advocates in their schools and communities for increased recess, physical education, recreational facilities, playgrounds, parks, and sidewalks.
It is also important for parents, children, and youth to take advantage of the opportunities for physical activity that come along throughout the day and to realize that not all physical activity has to be a planned event. Examples include walking to do errands or having children walk at the grocery store or mall rather than ride in shopping carts or strollers.
A complementary strategy for promoting physical activity among children and youth is to decrease their inactivity. Of the sedentary behaviors that may be linked to the upsurge in childhood obesity, television watching has been most widely studied. Other types of screen time (such as computer use and video game playing) have not been researched as extensively with regard to obesity, though they share many similarities in principle; various combinations, in fact, are often examined along with television in studies of media use and obesity. One study found that the time spent watching television, taped television shows, or commercial videos averaged per day: 2.5 hours for children between the ages of 2 and 7, 4.5 hours for 8- to 13-year-olds, and 3.3 hours for 14- to 18-year-olds (Roberts et al., 1999). The 2003 Youth Risk Behavior Surveillance nationwide survey found that 38.2 percent of high school students reported watching television three hours or longer on an average school day; 67.2 percent of African-American students, 45.9 percent of Hispanic students, and 29.3 percent of white students reported three or more hours of television viewing (CDC, 2004c).
Television viewing may have a negative effect on both sides of the energy balance equation. It may displace active play and physical activity time, and it is associated with increased food and calorie intake—as an accompaniment of television viewing, as a result of food advertising, or both (Robinson, 2001a). Many epidemiological studies have found positive associations between increased prevalence of obesity or overweight and greater lengths of television viewing time, although comparing the results is difficult due to differences in methods and reporting (reviewed by Robinson, 2001b). Gortmaker and colleagues (1996) found a strong positive association between parent or child reports of children’s television watching time and prevalence of obesity. This study of 746 children and youths (ages 10 to 15 years) found that those who watched more than five hours of television per day were 4.6 times as likely to be obese as those watching zero to two hours. This observation held when adjusted for maternal overweight, SES, and other factors.
Similarly, Crespo and colleagues (2001) found that in a sample of
4,069 children and adolescents aged 8 to 16 years, the prevalence of obesity was highest for those watching four or more hours of television a day and lowest among those watching one hour or less. Other studies have reported associations that were not statistically significant, but all have generally found associations of similar magnitude (reviewed by Robinson, 2001b). Dennison and colleagues (2002) found in a cross-sectional survey that children with televisions in their bedrooms spent an additional 4.6 hours per week watching television or videos. Furthermore, the investigators observed that the prevalence of BMIs greater than the 85th percentile was higher in children with a television in their bedroom than in those without one.
In attempting to determine how television viewing may promote childhood obesity, studies have examined the advertising of foods (particularly high-calorie, high-fat, or high-sugar foods and beverages), eating while watching television, decreased physical activity levels while viewing television, and the potential for physical activity that is lost due to time spent watching. An analysis of commercial advertising during children’s programming time (Saturday morning television, in this study) found that more than half of the commercials (56.5 percent) were for food (Kotz and Story, 1994). A recent review of the literature on food advertising to children found that the four primary categories of food items advertised are breakfast cereals, snacks, candy, and soft drinks (Hastings et al., 2003). Additionally, the authors found a recent trend towards increased advertising by fast food restaurants. Research has shown that television advertising influences children’s food knowledge, choices, and consumption of particular food products, as well as influencing purchase-related behavior and purchasing decisions (Gorn and Goldberg, 1982; Hastings et al., 2003).
Also, as noted earlier in this chapter, watching television during mealtime is associated with decreased intake of fruits and vegetables and increased consumption of soft drinks, salty snacks, pizza, and red meat (Coon et al., 2001). Children report consuming a large proportion of their daily calories while watching television, although there has not been evidence to date that the types or energy densities of foods that children eat while watching television differ significantly from those eaten when not watching (Matheson et al., 2004).
Studies of the nature and extent of associations between increased television viewing and decreased physical activity have produced inconsistent findings—possibly due, in part, to the known limitations of self- and parent-reporting on how children spend their time (Robinson, 2001b). A review by Sallis and colleagues (2000) noted that studies of children ages 4 to 12 had mixed results regarding the associations of sedentary behaviors (specifically, watching television and playing video games) with extent of physical activity, while in teenagers ages 13 to 18, there appeared to be no association. In one study of 191 3- to 4-year-olds that used direct observa-
tions of physical activity and television watching, physical activity levels were lowest during the longest periods of television watching (DuRant et al., 1994). In a study of sixth- and seventh-grade-girls, more hours of television watching was significantly but weakly associated with less reported physical activity (Robinson et al., 1993). Additionally, one experimental study of 13 8- to 12-year-old nonobese children did not find significant changes in short-term physical activity or energy expenditure when sedentary behavior (including television viewing) was decreased by 50 percent from baseline (Epstein et al., 2002). Natural experiments have found some evidence that introduction of television into communities where it did not exist previously does displace other more physical activities (Brown et al., 1974; Williams and Hanford, 1986). Thus, although a link between more screen time and less physical activity has face validity, clarification of this relationship must await the results of additional experimental studies with more objective measures.
Other factors that have been considered in the association of sedentary behaviors and obesity include computer use and video game play, parental patterns of sedentary behavior, parental monitoring of television viewing hours, and neighborhood characteristics such as safety of the area for outside play (Davison and Birch, 2001). Research has also been conducted to examine the possibility that television watching is associated with a decrease in children’s metabolic rates, but results from those studies have been mixed (Klesges et al., 1993; Dietz et al., 1994; Buchowski and Sun, 1996).
A few family-based interventions have focused on reducing sedentary behaviors, particularly television watching, to influence eating and activity patterns, and ultimately to produce weight loss. Early results from these studies have shown promise, but are still too preliminary for making conclusions about their efficacy (Robinson et al., 2003). Indirect evidence supporting this approach, however, has come from two studies by Epstein and colleagues (1995, 2000) that tested the effect of reducing sedentary behaviors as part of an intensive, family-based weight-loss program for children who were already overweight. The program showed effects on weight loss that were at least comparable to efforts that targeted increasing physical activity directly or targeted the combination of decreasing sedentary behavior and increasing physical activity. This study demonstrates the validity of targeting decreased inactivity as a potentially effective strategy that is distinct from strategies seeking to increase physical activity.
Of most direct relevance to recommendations for preventing obesity are experimental studies showing that reducing the amount of television viewing and other sedentary behaviors reduces weight gain and prevalence of obesity both among population-based samples of children and adolescents (Gortmaker et al., 1999; Robinson, 1999) and groups of overweight children (Epstein et al., 1995). From a primary prevention perspective, two
school-based interventions with population-based samples of children and adolescents demonstrated that reductions in screen time, whether alone (Robinson, 1999) or as part of a more comprehensive obesity prevention program (Gortmaker et al., 1999), resulted in decreased gain in BMI and body fatness and reduced prevalence of obesity.
Although the specific mechanism(s) of how reducing television viewing influences weight gain is, as yet, undetermined, these demonstrated effects on reduced weight gain and obesity provide sufficient rationale for the recommendation to reduce children’s screen time. The committee concludes that reducing children’s and youth’s screen time is an important population-based strategy for preventing obesity in children and youth, and that a time-limit recommendation would be most useful to parents, policy makers, and child health and education advocates and professionals. The committee notes that there are many ancillary reasons for recommending limits on children’s television viewing time (despite the demonstrated benefits of some media content). The American Academy of Pediatrics has recommended that televisions not be placed in children’s bedrooms, and it urges parents to limit their children’s television viewing time to no more than one to two hours of quality programming per day; it also recommends that television viewing among children younger than 2 years be discouraged altogether (AAP, 2001). Many other child and health advocacy organizations and agencies have made comparable recommendations for reductions in television and other screen viewing time for a variety of reasons including violent media content (APA and AAP, 1995; AMA, 1996; NEA, 1999; DHHS, 2000; AACAP, 2001; National PTA, 2001).
The committee recommends that parents should limit their children’s television viewing and recreational screen time to less than two hours per day. This specific time limit is derived from the evidence provided by the two school-based primary prevention intervention studies that demonstrated reductions in body weight, body fat, and prevalence of obesity. The interventions in those trials set goals to limit television, videotape, and video game use to no more than seven hours per week (Robinson, 1999) and to limit television viewing to less than two hours in any one day (Gortmaker et al., 1999). (It should be noted that a key word here is “recreational.” The committee’s recommendation does not preclude the use of computers and other media for educational purposes.)
An important part of parenting involves monitoring children’s behaviors and setting and enforcing limits on those behaviors. Such family policies should be set for a variety of reasons, including the protection of young children (e.g., keeping them from playing in the street) and assurance of their healthy development. Naturally, there is great variation in the nature and extent to which parents set limits and how those limits change as the child matures. One challenge for parents of older children is knowing how
to involve them in decision-making so that they learn to apply limits for themselves; they should come to realize, for example, that they are responsible for their own health and need to practice health-promoting behaviors. But in the current food and activity environment—where palatable, energydense, and inexpensive foods are readily available and opportunities for sedentary behaviors are abundant—a degree of parental monitoring and limit setting is still needed to support eating and physical activity patterns that can maintain children’s energy balance at a healthy weight.
PARENTS AS ROLE MODELS
Parents’ eating behaviors can serve as models for children’s behavior (Fisher and Birch, 1995; Cutting et al., 1999). Such models, however, can be either positive or negative. The current epidemic of adult obesity and the epidemiological data on adults’ dietary and physical activity patterns suggest cause for concern (CDC, 2004a,b). But the public’s growing awareness of the obesity epidemic and of the health consequences of obesity, in children and adults alike, may change these patterns. When parents adopt a healthier lifestyle, they may foster the development of healthful behaviors and patterns in their children, in addition to positively affecting their own well-being. Researchers have provided evidence that modeling and enhanced familiarity have independent significant effects on food intake (Cullen et al., 2000, 2003). With respect to physical activity, the provision of instrumental support for children’s sports participation is associated with greater levels of physical activity among children (Davison et al., 2003).
Parents who consume fruits and vegetables, for example, have children who do the same (Cullen et al., 2001; Nicklas et al., 2001; Fisher et al., 2002). Comparable patterns are seen with milk intake, at least for mothers and daughters (Fisher et al., 2001). Similarly, parents who display their mastery of portion control can provide positive influences. Hill and colleagues have reported that mothers who diet or are restrained eaters tend to have daughters who show the same kinds of patterns (Hill et al., 1990; Pike and Rodin, 1991). Abramovitz and Birch (2000) found that mothers’ dieting is the best predictor of their 5-year-old daughters’ knowledge of dieting. Cutting and colleagues (1999) showed that familial similarities in mothers’ and daughters’ overweight status are mediated by similarities in “disinhibited overeating” (overeating in the absence of hunger).
As discussed earlier in this chapter, parents who are supportive of physical activity have children who are more physically active (Sallis et al., 1988; Davison et al., 2003). However, evidence for a direct effect of parent modeling on youth physical activity is inconsistent at best. This is in contrast to the stronger evidence for modeling regarding eating patterns. The discrepant findings may be explained by different mediators. If parents are
eating fruits and vegetables and drinking milk, it means those foods are readily available to the child. However, parents often engage in different types of physical activities than children or in different settings, so the parent going to a health club or on a run may not facilitate the child’s physical activity and could serve as a barrier.
Researchers have compared the effects of different families’ eating and activity patterns on their children. Families can be categorized as either “obesogenic,” where physical activity is relatively low and energy and fat intakes are high, or nonobesogenic, where parents show higher levels of activity and lower energy intakes. For example, in one study, girls living in obesogenic families gained more weight from age 5 to 7 than girls from nonobesogenic families, and the former were more likely to be overweight at age 7 (Davison and Birch, 2002). These effects were mediated by similarities in mother-daughter eating patterns and father-daughter physical activity patterns, suggesting that while mothers were effective models for daughters’ eating habits, fathers’ levels of physical activity influenced their daughters in that area.
It is not known to what extent the observed effects of modeling reflect modeling per se or result simply from the fact that parents either do or do not establish routine access to healthful options so that these options are familiar to their children. That is, parents who eat a healthful diet and are active typically provide access to healthful food and opportunities for physical activity for their children as well. As discussed in Chapter 3, guidance regarding a balanced diet and regular physical activity is available through the Dietary Guidelines for Americans.
Parents should provide positive role models of eating and physical activity behaviors for their children. The committee urges parents to be positive role models for their children by decreasing the amount of time they engage in sedentary activities such as watching TV, increasing the amount of time they engage in physical activity each day, and modeling eating habits that include balance and variety in their food choices and portion control.
RAISING AWARENESS OF WEIGHT AS A HEALTH ISSUE
It is critically important that parents view childhood obesity as a health issue and realize that obesity can have a deleterious impact on physical as well as mental health, both during childhood and later in life. Yet parents of overweight or obese children do not always recognize their child’s weight status and many are not fully aware of its adverse consequences (Young-Hyman et al., 2000; Etelson et al., 2003; Maynard et al., 2003).
Because children often exhibit idiosyncratic growth patterns, it is important to evaluate a child within the context of his or her own particular
growth history as well as relative to a healthy and appropriate reference population. For individuals under 20 years of age, BMI is a complex concept; not only do weight and height change as the body grows, but body-fat content and muscular development are also changing, and there are significant gender differences in the pattern of change. Thus it is important to use gender- and age-specific BMI percentiles to determine whether a particular child has excess weight.
During infancy, parents tend to be well aware of their child’s weight and height, and it is not unusual for them to know where his or her measurements fall on the health-care provider’s growth curves, which are derived from reference populations of healthy children of the same age and sex. However, as children grow, and particularly in the late elementary and middle- and high school years, this information often is not familiar to parents—unless they think their child is failing to grow, which may sensitize them to the need for careful monitoring and tracking. Parents may also notice particular periods of height change, as when the child rapidly outgrows his or her clothes. Because of the variable timing of growth spurts, and the sometimes dramatic changes in body composition with age, continued monitoring of growth on an annual basis is warranted; if concerns arise about the child’s growth trajectory, parents should then discuss these issues with a qualified health-care professional.
Routine determination of children’s BMI percentile, and regular communication between parents and health-care providers regarding their child’s BMI-percentile history and current status, are crucial to increasing the knowledge base of parents regarding their child’s growth pattern and weight status. Parents also need to be aware of the strong connection between good nutrition and physical activity to the child’s weight—and to his or her health. If excessive weight gain is observed, it is important for parents to discuss follow-up steps and behavior changes with their child’s health-care provider (see Chapter 6). These discussions should be sensitive to parental concerns about the stigma of obesity and its potential impact on the child’s self-esteem and should take care to allay concerns about eating disorders (Borra et al., 2003).
Just as vaccination schedules require parental intervention during childhood, parents should be discussing the prevention of obesity with their health-care providers to make sure that the child is on a healthy growth track. Parents should consider the weight of their children to be a critically important indicator of health. They should ensure that a trained professional routinely (at least once a year) measures their child’s height and weight in order to track his or her age- and gender-specific BMI percentile.
But given that many families do not have the health insurance to cover preventive services, and these types of health-care visits may therefore impose a financial burden, the committee also recommends (in Chapter 7)
that schools conduct periodic assessments of students’ weight status and provide the resulting information to parents—and to the children themselves, as age-appropriate.
Home environments that support healthful eating and physical activity are important in helping children maintain energy balance at a healthy weight. Preventing childhood obesity starts with a healthful diet and lifestyle at conception and throughout pregnancy and is promoted by exclusive breastfeeding during infancy. As discussed throughout this chapter, parents can ensure that healthful foods are available in the home and that healthful eating behaviors (e.g., family meals, limited snacking, and portion control) are promoted. Older children and youth must be aware of their own eating habits and activity patterns and engage in health-promoting behaviors. By being supportive of their children’s athletic and other interests in physical activity and by encouraging children to play outside, parents can enhance opportunities for moderate to vigorous physical activity and promote physical fitness. Furthermore, parents can set a good example for their children by modeling healthful eating behaviors and being physically active. Parents can also be effective advocates by becoming involved in efforts in their neighborhoods, schools, and community to improve neighborhood safety and to expand the access and availability of opportunities such as recreational facilities, playgrounds, sidewalks, bike paths, and farmers’ markets (Chapters 6 and 7).
Recommendation 10: Home
Parents should promote healthful eating behaviors and regular physical activity for their children.
To implement this recommendation parents can:
Choose exclusive breastfeeding as the method for feeding infants for the first four to six months of life
Provide healthful food and beverage choices for children by carefully considering nutrient quality and energy density
Assist and educate children in making healthful decisions regarding types of foods and beverages to consume, how often, and in what portion size
Encourage and support regular physical activity
Limit children’s television viewing and other recreational screen time to less than two hours per day
Discuss weight status with their child’s health-care provider and monitor age- and gender-specific BMI percentile
Serve as positive role models for their children regarding eating and physical activity behaviors
AACAP (American Academy of Child and Adolescent Psychiatry). 2001. Children and Watching TV. Facts for Families, No. 54. [Online]. Available: http://www.aacap.org/publications/factsfam/tv.htm [accessed June 7, 2004].
AAP (American Academy of Pediatrics). 2001. Children, adolescents, and television. Pediatrics 107(2):423-426.
AAP. 2003. Prevention of pediatric overweight and obesity. Pediatrics 112(2):424-430.
AAP. 2004. Pediatric Nutrition Handbook. 5th ed. Washington, DC: AAP.
Abramovitz BA, Birch LL. 2000. Five-year-old girls’ ideas about dieting are predicted by their mothers’ dieting. J Am Diet Assoc 100(10):1157-1163.
ADA (American Dietetic Association). 2004. Position of the American Dietetic Association: Dietary guidance for healthy children ages 2 to 11 years. J Am Diet Assoc 104(4):660-677.
AMA (American Medical Association). 1996. Physician Guide to Media Violence. Chicago, IL: AMA.
APA (American Psychological Association), AAP (American Academy of Pediatrics). 1995. Raising Children to Resist Violence: What You Can Do. Washington, DC: APA and AAP.
Baranowski T, Simons-Morton B, Hooks P, Henske J, Tiernan K, Dunn JK, Burkhalter H, Harper J, Palmer J. 1990. A center-based program for exercise change among black-American families. Health Educ Q 17(2):179-196.
Baranowski T, Thompson WO, DuRant RH, Baranowski J, Puhl J. 1993. Observations on physical activity in physical locations: Age, gender, ethnicity, and month effects. Res Q Exerc Sport 64(2):127-133.
Baranowski T, Davis M, Resnicow K, Baranowski J, Doyle C, Lin LS, Smith M, Wang DT. 2000. Gimme 5 fruit, juice, and vegetables for fun and health: Outcome evaluation. Health Educ Behav 27(1):96-111.
Beauchamp GK, Cowart BJ. 1985. Congenital and experiential factors in the development of human flavor preferences. Appetite 6(4):357-372.
Bergmann KE, Bergmann RL, von Kries R, Bohm O, Richter R, Dudenhausen JW, Wahn U. 2003. Early determinants of childhood overweight and adiposity in a birth cohort study: Role of breast-feeding. Int J Obes Relat Metab Disord 27(2):162-172.
Birch LL. 1981. Generalization of a modified food preference. Child Dev 52:755-758.
Birch LL. 1999. Development of food preferences. Annu Rev Nutr 19:41-62.
Birch LL, Marlin DW. 1982. I don’t like it; I never tried it: Effects of exposure on two-year-old children’s food preferences. Appetite 3(4):353-360.
Birch LL, Zimmerman S, Hind H. 1980. The influence of social-affective context on preschool children’s food preferences. Child Dev 51:856-861.
Birch LL, McPhee L, Shoba BC, Pirok E, Steinberg L. 1987. What kind of exposure reduces children’s food neophobia? Looking vs. tasting. Appetite 9(3):171-178.
Bishop P, Donnelly JE. 1987. Home based activity program for obese children. Am Correct Ther J 41(1):12-19.
Bogen DL, Hanusa BH, Whitaker RC. 2004. The effect of breast-feeding with and without concurrent formula use on the risk of obesity at 4 years of age. Obes Res 12:1528-1536.
Borra ST, Kelly L, Shirreffs MB, Neville K, Geiger CJ. 2003. Developing health messages: Qualitative studies with children, parents, and teachers help identify communications opportunities for healthful lifestyles and the prevention of obesity. J Am Diet Assoc 103(6):721-728.
Brown JR, Cramond JK, Wilde RJ. 1974. Displacment effects of television and the child’s functional orientation to the media. In: Blumler JG, Katz E, eds. The Uses of Mass Communications: Current Perspectives on Gratifications Research. Beverly Hills, CA: Sage Publications. Pp. 93-112.
Buchowski MS, Sun M. 1996. Energy expenditure, television viewing and obesity. Int J Obes 20(3):236-244.
Butcher JE, Eaton WO. 1989. Gross motor proficiency in preschoolers: Relationships with free play behavior and activity level. J Hum Movement Stud 16:27-36.
Cavadini C, Siega-Riz AM, Popkin BM. 2000. US adolescent food intake trends from 1965 to 1996. Arch Dis Child 83(1):18-24.
CDC (Centers for Disease Control and Prevention). 1997. Guidelines for school and community programs to promote lifelong physical activity among young people. MMWR Recomm Rep 46(RR-6):1-36.
CDC. 2004a. Prevalence of no leisure-time physical activity—35 states and the District of Columbia, 1988-2002. MMWR 53(4):82-86.
CDC. 2004b. Trends in intake of energy and macronutrients—United States, 1971-2000. MMWR 53(4):80-82.
CDC. 2004c. Youth risk behavior surveillance—United States, 2003. MMWR Surveill Summ 53(SS-2):1-96.
Coates TJ, Killen JD, Slinkard LA. 1982. Parent participation in a treatment program for overweight adolescents. Int J Eat Disord 1(3):37-48.
Coon KA, Goldberg J, Rogers BL, Tucker KL. 2001. Relationships between use of television during meals and children’s food consumption patterns. Pediatrics 107(1):E7.
Cowart BJ. 1981. Development of taste perception in humans: Sensitivity and preference throughout the life span. Psychol Bull 90:43-73.
Crespo CJ, Smit E, Troiano RP, Bartlett SJ, Macera CA, Andersen RE. 2001. Television watching, energy intake, and obesity in US children: Results from the third National Health and Nutrition Examination Survey, 1988-1994. Arch Pediatr Adolesc Med 155(3):360-365.
Cullen KW, Baranowski T, Rittenberry L, Olvera N. 2000. Social-environmental influences on children’s diets: Results from focus groups with African-, Euro- and Mexican-American children and their parents. Health Educ Res 15(5):581-590.
Cullen KW, Baranowski T, Rittenberry L, Cosart C, Hebert D, de Moor C. 2001. Child-reported family and peer influences on fruit, juice and vegetable consumption: Reliability and validity of measures. Health Educ Res 16(2):187-200.
Cullen KW, Baranowski T, Owens E, Marsh T, Rittenberry L, de Moor C. 2003. Availability, accessibility, and preferences for fruit, 100% fruit juice, and vegetables influence children’s dietary behavior. Health Educ Behav 30(5):615-626.
Cutting TM, Fisher JO, Grimm-Thomas K, Birch LL. 1999. Like mother, like daughter: Familial patterns of overweight are mediated by mothers’ dietary disinhibition. Am J Clin Nutr 69(4):608-613.
Davis SM, Lambert LC, Gomez Y, Skipper B. 1995. Southwest Cardiovascular Curriculum Project: Study findings for American Indian elementary students. J Health Educ 26(Suppl):S72-S81.
Davison KK, Birch LL. 2001. Childhood overweight: A contextual model and recommendations for future research. Obes Rev 2(3):159-171.
Davison KK, Birch LL. 2002. Obesigenic families: Parents’ physical activity and dietary intake patterns predict girls’ risk of overweight. Int J Obes Relat Metab Disord 26(9):1186-1193.
Davison KK, Cutting TM, Birch LL. 2003. Parents’ activity-related parenting practices predict girls’ physical activity. Med Sci Sports Exerc 35(9):1589-1595.
Dennison BA, Erb TA, Jenkins PL. 2002. Television viewing and television in bedroom associated with overweight risk among low-income preschool children. Pediatrics 109(6):1028-1035.
Devine CM, Connors MM, Sobal J, Bisogni CA. 2003. Sandwiching it in: Spillover of work onto food choices and family roles in low- and moderate-income urban households. Soc Sci Med 56(3):617-630.
Dewey KG. 2003. Is breastfeeding protective against child obesity? J Hum Lact 19(1):9-18.
DHHS (U.S. Department of Health and Human Services). 1996. Physical Activity and Health: A Report of the Surgeon General. Atlanta, GA: CDC.
DHHS, Agency for Health Care Policy and Research. 2000. Child Health Guide: Put Prevention into Practice. Rockville, MD: Agency for Health Care Policy and Research. [Online]. Available: http://www.ahrq.gov/ppip/childguide/ [accessed June 10, 2004].
Dietz WH, Bandini LG, Morelli JA, Peers KF, Ching PL. 1994. Effect of sedentary activities on resting metabolic rate. Am J Clin Nutr 59(3):556-559.
Diliberti N, Bordi PL, Conklin MT, Roe LS, Rolls BJ. 2004. Increased portion size leads to increased energy intake in a restaurant meal. Obes Res 12(3):562-568.
DiLorenzo TM, Stucky-Ropp RC, Vander Wal JS, Gotham HJ. 1998. Determinants of exercise among children. II. A longitudinal analysis. Prev Med 27(3):470-477.
DuRant RH, Baranowski T, Johnson M, Thompson WO. 1994. The relationship among television watching, physical activity, and body composition of young children. Pediatrics 94(4 Pt 1):449-455.
Edmundson E, Parcel GS, Feldman HA, Elder J, Perry CL, Johnson CC, Williston BJ, Stone EJ, Yang M, Lytle L, Webber L. 1996. The effects of the Child and Adolescent Trial for Cardiovascular Health upon psychosocial determinants of diet and physical activity behavior. Prev Med 25(4):442-454.
Epstein LH, Valoski A, Wing RR, McCurley J. 1990. Ten-year follow-up of behavioral, family-based treatment for obese children. J Am Med Assoc 264(19):2519-2523.
Epstein LH, Valoski A, Wing RR, McCurley J. 1994. Ten-year outcomes of behavioral family-based treatment for childhood obesity. Health Psychol 13(5):373-383.
Epstein LH, Valoski AM, Vara LS, McCurley J, Wisniewski L, Kalarchian MA, Klein KR, Shrager LR. 1995. Effects of decreasing sedentary behavior and increasing activity on weight change in obese children. Health Psychol 14(2):109-115.
Epstein LH, Paluch RA, Gordy CC, Dorn J. 2000. Decreasing sedentary behaviors in treating pediatric obesity. Arch Pediatr Adolesc Med 154(3):220-226.
Epstein LH, Paluch RA, Consalvi A, Riordan K, Scholl T. 2002. Effects of manipulating sedentary behavior on physical activity and food intake. J Pediatr 140(3):334-339.
Etelson D, Brand DA, Patrick PA, Shirali A. 2003. Childhood obesity: Do parents recognize this health risk? Obes Res 11(11):1362-1368.
Fields J. 2003. Children’s Living Arrangements and Characteristics: March 2002. Current Population Reports. Washington, DC: U.S. Census Bureau.
Fisher JO, Birch LL. 1995. Fat preferences and fat consumption of 3- to 5-year-old children are related to parental adiposity. J Am Diet Assoc 95(7):759-764.
Fisher JO, Birch LL. 1999. Restricting access to foods and children’s eating. Appetite 32(3):405-419.
Fisher JO, Birch LL, Smiciklas-Wright H, Picciano MF. 2000. Breast-feeding through the first year predicts maternal control in feeding and subsequent toddler energy intakes. J Am Diet Assoc 100(6):641-646.
Fisher JO, Mitchell DC, Smiciklas-Wright H, Birch LL. 2001. Maternal milk consumption predicts the tradeoff between milk and soft drinks in young girls’ diets. J Nutr 131(2):246-250.
Fisher JO, Mitchell DC, Smiciklas-Wright H, Birch LL. 2002. Parental influences on young girls’ fruit and vegetable, micronutrient, and fat intakes. J Am Diet Assoc 102(1):58-64.
Fomon SJ, Filer LJ, Thomas LN, Anderson TA, Nelson SE. 1975. Influence of formula concentration on caloric intake and growth of normal infants. Acta Paediatr Scand 64(2):172-181.
Forshee RA, Storey ML. 2003. Total beverage consumption and beverage choices among children and adolescents. Int J Food Sci Nutr 54(4):297-307.
Fox MK, Pac S, Devaney B, Jankowski L. 2004. Feeding infants and toddlers study: What foods are infants and toddlers eating? J Am Diet Assoc 104(1 Suppl 1):S22-S30.
French SA, Lin BH, Guthrie JF. 2003. National trends in soft drink consumption among children and adolescents age 6 to 17 years: Prevalence, amounts, and sources, 1977/ 1978 to 1994/1998. J Am Diet Assoc 103(10):1326-1331.
French SA, Hannan PJ, Story M. 2004. School soft drink intervention study. Br Med J 329(7462):E315-E316.
Galst J, White M. 1976. The unhealthy persuader: The reinforcing value of television and children’s purchase influencing attempts at the supermarket. Child Dev 47:1089-1096.
Gillman MW, Rifas-Shiman SL, Frazier AL, Rockett HR, Camargo CA Jr, Field AE, Berkey CS, Colditz GA. 2000. Family dinner and diet quality among older children and adolescents. Arch Fam Med 9(3):235-240.
Gillman MW, Rifas-Shiman S, Berkey CS, Field AE, Colditz GA. 2003. Maternal gestational diabetes, birth weight, and adolescent obesity. Pediatrics 111(3):e221-e226.
Gleason P, Suitor C. 2001. Children’s Diets in the Mid-1990’s: Dietary Intake and Its Relationship with School Meal Participation. Report No. CN-01-CD1. Alexandria, VA: USDA.
Golan M, Crow S. 2004. Targeting parents exclusively in the treatment of childhood obesity: Long-term results. Obes Res 12(2):357-361.
Golan M, Weizman A, Apter A, Fainaru M. 1998. Parents as the exclusive agents of change in the treatment of childhood obesity. Am J Clin Nutr 67(6):1130-1135.
Goran MI, Reynolds KD, Lindquist CH. 1999. Role of physical activity in the prevention of obesity in children. Int J Obes Relat Metab Disord 23(Suppl 3):S18-S33.
Gordon-Larsen P, McMurray RG, Popkin BM. 2000. Determinants of adolescent physical activity and inactivity patterns. Pediatrics 105(6):E83.
Gorn GJ, Goldberg ME. 1982. Behavioral evidence for the effects of televised food messages on children. J Consumer Res 9:200-205.
Gortmaker SL, Must A, Sobol AM, Peterson K, Colditz GA, Dietz WH. 1996. Television viewing as a cause of increasing obesity among children in the United States, 1986-1990. Arch Pediatr Adolesc Med 150(4):356-362.
Gortmaker SL, Peterson K, Wiecha J, Sobol AM, Dixit S, Fox MK, Laird N. 1999. Reducing obesity via a school-based interdisciplinary intervention among youth: Planet Health. Arch Pediatr Adolesc Med 153(4):409-418.
Graber JA, Brooks-Gunn J. 1996. Prevention of eating problems and disorders: Including parents. Eat Disord 4(4):348-363.
Grummer-Strawn LM, Mei Z. 2004. Does breastfeeding protect against pediatric overweight? Analysis of longitudinal data from the Centers for Disease Control and Prevention Pediatric Nutrition Surveillance System. Pediatrics 113(2):e81-e86.
Guthrie JF, Morton JF. 2000. Food sources of added sweeteners in the diets of Americans. J Am Diet Assoc 100(1):43-51.
Gutin B, Barbeau P, Yin Z. 2004. Exercise interventions for prevention of obesity and related disorders in youths. Quest 56:120-141.
Hastings G, Stead M, McDermott L, Forsyth A, MacKintosh A, Rayner, M, Godfrey C, Caraher M, Angus K. 2003. Review of Research on the Effects of Food Promotion to Children. Glasgow, UK: Center for Social Marketing, University of Strathclyde. Available: http://www.food.gov.uk/multimedia/pdfs/foodpromotiontochildren1.pdf [accessed November 22, 2003].
Hewlett SA, West C. 1998. The War Against Parents. New York: Houghton Mifflin.
Hill AJ, Weaver C, Blundell JE. 1990. Dieting concerns of 10-year-old girls and their mothers. Br J Clin Psychol 29(Pt 3):346-348.
Hopper CA, Gruber MB, Munoz KD, Herb RA. 1992. Effect of including parents in a school-based exercise and nutrition program for children. Res Q Exerc Sport 63(3):315-321.
Hopper CA, Munoz KD, Gruber MB, MacConnie SE, Schonfeldt B, Shunk T. 1996. A school-based cardiovascular exercise program with parent participation: An evaluation study. Child Health Care 25(3):221-235.
IOM (Institute of Medicine). 2002. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press.
James J, Thomas P, Cavan D, Kerr D. 2004. Preventing childhood obesity by reducing consumption of carbonated drinks: Cluster randomized controlled trial. Br Med J 328(7450):1237.
Johnson CC, Nicklas TA, Arbeit ML, Harsha DW, Mott DS, Hunter SM, Wattigney W, Berenson GS. 1991. Cardiovascular intervention for high-risk families: The Heart Smart Program. South Med J 84(11):1305-1312.
Johnson SL, McPhee L, Birch LL. 1991. Conditioned preferences: Young children prefer flavors associated with high dietary fat. Physiol Behav 50(6):1245-1251.
Kahn EB, Ramsey LT, Brownson RC, Heath GW, Howze EH, Powell KE, Stone EJ, Rajab MW, Corso P. 2002. The effectiveness of interventions to increase physical activity. A systematic review. Am J Prev Med 22(4 Suppl):73-107.
Kirschenbaum DS, Harris ES, Tomarken AJ. 1984. Effects of parental involvement in behavioral weight loss therapy for preadolescents. Behav Ther 15(5):485-500.
Klesges RC, Eck LH, Hanson CL, Haddock CK, Klesges LM. 1990. Effects of obesity, social interactions, and physical environment on physical activity in preschoolers. Health Psychol 9(4):435-449.
Klesges RC, Shelton ML, Klesges LM. 1993. Effects of television on metabolic rate: Potential implications for childhood obesity. Pediatrics 91(2):281-286.
Kohl HW, Hobbs KE. 1998. Development of physical activity behaviors among children and adolescents. Pediatrics 101(3 Pt 2):549-554.
Koivisto UK, Fellenius J, Sjoden PO. 1994. Relations between parental mealtime practices and children’s food intake. Appetite 22(3):245-257.
Kotz K, Story M. 1994. Food advertisements during children’s Saturday morning television programming: Are they consistent with dietary recommendations? J Am Diet Assoc 94(11):1296-1300.
Lederman SA, Akabas S, Moore BJ, Bentley ME, Devaney B, Gillman MW, Kramer MS, Mennella JA, Ness A, Wardle J. 2004. Summary of the presentations at the Conference on Preventing Childhood Obesity, December 8, 2003. Pediatrics 114:1146-1173.
Lindquist CH, Reynolds KD, Goran MI. 1999. Sociocultural determinants of physical activity among children. Prev Med 29(4):305-312.
Lissau I, Sorensen TI. 1994. Parental neglect during childhood and increased risk of obesity in young adulthood. Lancet 343(8893):324-327.
Loewen R, Pliner P. 1999. Effects of prior exposure to palatable and unpalatable novel foods on children’s willingness to taste other novel foods. Appetite 32(3):351-366.
Ludwig DS, Peterson KE, Gortmaker SL. 2001. Relation between consumption of sugar-sweetened drinks and childhood obesity: A prospective, observational analysis. Lancet 357(9255):505-508.
Manios Y, Moschandreas J, Hatzis C, Kafatos A. 1999. Evaluation of a health and nutrition education program in primary school children of Crete over a three-year period. Prev Med 28(2):149-159.
Matheson DM, Killen JD, Wang Y, Varady A, Robinson TN. 2004. Children’s food consumption during television viewing. Am J Clin Nutr 79(6):1088-1094.
Maynard LM, Galuska DA, Blanck HM, Serdula MK. 2003. Maternal perceptions of weight status of children. Pediatrics 111(5 Pt 2):1226-1231.
McConahy KL, Smiciklas-Wright H, Birch LL, Mitchell DC, Picciano MF. 2002. Food portions are positively related to energy intake and body weight in early childhood. J Pediatr 140(3):340-347.
McGuire MT, Hannan PJ, Neumark-Sztainer D, Cossrow NH, Story M. 2002. Parental correlates of physical activity in a racially/ethnically diverse adolescent sample. J Adolesc Health 30(4):253-261.
Mennella JA. 1995. Mother’s milk: A medium for early flavor experiences. J Hum Lact 11(1):39-45.
Mennella JA, Beauchamp GK. 1991. Maternal diet alters the sensory qualities of human milk and the nursling’s behavior. Pediatrics 88(4):737-744.
Mennella JA, Beauchamp GK. 1998. Early flavor experiences: Research update. Nutr Rev 56(7):205-211.
Mennella JA, Jagnow CP, Beauchamp GK. 2001. Prenatal and postnatal flavor learning by human infants. Pediatrics 107:E88.
Motl RW, Dishman RK, Ward DS, Saunders RP, Dowda M, Felton G, Pate RR. 2002. Examining social-cognitive determinants of intention and physical activity among black and white adolescent girls using structural equation modeling. Health Psychol 21(5):459-467.
Nader PR, Baranowski T, Vanderpool NA, Dunn K, Dworkin R, Ray L. 1983. The Family Health Project: Cardiovascular risk reduction education for children and parents. J Dev Behav Pediatr 4(1):3-10.
Nader PR, Sallis JF, Patterson TL, Abramson IS, Rupp JW, Senn KL, Atkins CJ, Roppe BE, Morris JA, Wallace JP, Vega WA. 1989. A family approach to cardiovascular risk reduction: Results from the San Diego Family Health Project. Health Educ Q 16(2):229-244.
National PTA (National Parent Teachers Association), Cable in the Classroom, National Cable and Telecommunications Association. 2001. Taking Charge of Your TV: A Guide to Critical Viewing for Parents and Children. [Online]. Available: http://www.ciconline.com/Enrichment/MediaLiteracy/TakingCharge/ParentsGuide/default.htm [accessed July 6, 2004].
NEA (National Education Association). 1999. 52 Ways to Help Your Child Learn. Washington, DC: NEA.
Nestle M. 2003. Increasing portion sizes in American diets: More calories, more obesity. J Am Diet Assoc 103(1):39-40.
Neumark-Sztainer D, Hannan PJ, Story M, Croll J, Perry C. 2003a. Family meal patterns: Associations with sociodemographic characteristics and improved dietary intake among adolescents. J Am Diet Assoc 103(3):317-322.
Neumark-Sztainer D, Story M, Hannan PJ, Tharp T, Rex J. 2003b. Factors associated with changes in physical activity: A cohort study of inactive adolescent girls. Arch Pediatr Adolesc Med 157(8):803-810.
Nicklas TA, Baranowski T, Baranowski JC, Cullen K, Rittenberry L, Olvera N. 2001. Family and child-care provider influences on preschool children’s fruit, juice, and vegetable consumption. Nutr Rev 59(7):224-235.
Orlet-Fisher J, Rolls BJ, Birch LL. 2003. Children’s bite size and intake of an entree are greater with large portions than with age-appropriate or self-selected portions. Am J Clin Nutr 77(5):1164-1170.
Parke RD, Buriel R. 1998. Socialization in the family: Ethnic and ecological perspectives. In: Damon W, ed. Handbook of Child Psychology. 5th ed. New York: Wiley.
Pate RR, Heath GW, Dowda M, Trost SG. 1996. Associations between physical activity and other health behaviors in a representative sample of US adolescents. Am J Public Health 86(11):1577-1581.
Pate RR, Trost SG, Felton GM, Ward DS, Dowda M, Saunders R. 1997. Correlates of physical activity behavior in rural youth. Res Q Exerc Sport 68(3):241-248.
Pica R. 1997. Beyond physical development: Why young children need to move. Young Child 52(6):4-11.
Pike KM, Rodin J. 1991. Mothers, daughters, and disordered eating. J Abnorm Psychol 100(2):198-204.
Rampersaud GC, Bailey LB, Kauwell GPA. 2003. National survey beverage consumption data for children and adolescents indicate the need to encourage a shift toward more nutritive beverages. J Am Diet Assoc 103(1):97-100.
Roberts D, Foehr U, Rideout V, Brodie M. 1999. Kids and Media at the New Millennium. Menlo Park, CA: The Henry J. Kaiser Family Foundation. [Online]. Available: http://www.kff.org/content/1999/1535/KidsReport%20FINAL.pdf [accessed April 15, 2004].
Robinson TN. 1999. Reducing children’s television viewing to prevent obesity: A randomized controlled trial. J Am Med Assoc 282(16):1561-1567.
Robinson TN. 2001a. Population-based obesity prevention for children and adolescents. In: Johnston FE, Foster GD, eds. Obesity, Growth and Development. London: Smith-Gordon. Pp. 129-141.
Robinson TN. 2001b. Television viewing and childhood obesity. Pediatr Clin North Am 48(4):1017-1025.
Robinson TN, Hammer LD, Killen JD, Kraemer HC, Wilson DM, Hayward C, Taylor CB. 1993. Does television viewing increase obesity and reduce physical activity? Cross-sectional and longitudinal analyses among adolescent girls. Pediatrics 91(2):273-280.
Robinson TN, Killen JD, Kraemer HC, Wilson DM, Matheson DM, Haskell WL, Pruitt LA, Powell TM, Owens AS, Thompson NS, Flint-Moore NM, Davis GJ, Emig KA, Brown RT, Rochon J, Green S, Varady A. 2003. Dance and reducing television viewing to prevent weight gain in African-American girls: The Stanford GEMS pilot study. Ethn Dis 13(1 Suppl 1):S1.65-S1.77.
Rolls BJ. 2003. The supersizing of America. Portion size and the obesity epidemic. Nutr Tod 38(2):42-53.
Rolls BJ, Engell D, Birch LL. 2000. Serving portion size influences 5-year-old but not 3-year-old children’s food intakes. J Am Diet Assoc 100(2):232-234.
Roper ASW. 2003. 2003 Roper Youth Report. New York. [Online]. Available: http://www.roperasw.com/newsroom/press/p0310002.html [accessed May 3, 2004].
Sallis JF, Patterson TL, Buono MJ, Atkins CJ, Nader PR. 1988. Aggregation of physical activity habits in Mexican-American and Anglo families. J Behav Med 11(1):31-41.
Sallis JF, Simons-Morton BG, Stone EJ, Corbin CB, Epstein LH, Faucette N, Iannotti RJ, Killen JD, Klesges RC, Petray CK, Rowland TW, Taylor WC. 1992. Determinants of physical activity and interventions in youth. Med Sci Sports Exerc 24(6 Suppl):S249-S257.
Sallis JF, Nader PR, Broyles SL, Berry CC, Elder JP, McKenzie TL, Nelson JA. 1993. Correlates of physical activity at home in Mexican-American and Anglo-American preschool children. Health Psychol 12(5):390-398.
Sallis JF, McKenzie TL, Alcaraz JE, Kolody B, Faucette N, Hovell MF. 1997. The effects of a 2-year physical education program (SPARK) on physical activity and fitness in elementary school students. Sports, Play and Active Recreation for Kids. Am J Public Health 87(8):1328-1334.
Sallis JF, Alcaraz JE, McKenzie TL, Hovell MF. 1999. Predictors of change in children’s physical activity over 20 months. Variations by gender and level of adiposity. Am J Prev Med 16(3):222-229.
Sallis JF, Prochaska JJ, Taylor WC. 2000. A review of correlates of physical activity of children and adolescents. Med Sci Sports Exerc 32(5):963-975.
Schmitz KH, Lytle LA, Phillips GA, Murray DM, Birnbaum AS, Kubik MY. 2002. Psychosocial correlates of physical activity and sedentary leisure habits in young adolescents: The Teens Eating for Energy and Nutrition at School study. Prev Med 34(2):266-278.
Shape Up America! 2004. 99 Tips for Family Fitness Fun. [Online]. Available: http://www.shapeup.org/pubs/99tips/index.html [accessed June 24, 2004].
Silverman BL, Cho NH, Rizzo TA, Metzger BE. 1998. Long-term effects of the intrauterine environment: The Northwestern University Diabetes in Pregnancy Center. Diab Care 21(S2):B142-B149.
Skinner JD, Carruth BR, Bounds W, Ziegler P, Reidy K. 2002. Do food-related experiences in the first 2 years of life predict dietary variety in school-aged children? J Nutr Educ Behav 34(6):310-315.
Smiciklas-Wright H, Mitchell D, Mickle S, Goldman J, Cook A. 2003. Foods commonly eaten in the United States, 1989-1991 and 1994-1996: Are portion sizes changing? J Am Diet Assoc 103(1):41-47.
Smith K. 2002. Who’s Minding the Kids? Child Care Arrangements: Spring 1997. Current Population Reports P70-86. Washington, DC: U.S. Census Bureau.
Stettler N, Zemel BS, Kumanyika S, Stallings VA. 2002. Infant weight gain and childhood overweight status in a multicenter, cohort study. Pediatrics 109(2):194-199.
Stettler N, Kumanyika SK, Katz SH, Zemel BS, Stallings VA. 2003. Rapid weight gain during infancy and obesity in young adulthood in a cohort of African Americans. Am J Clin Nutr 77(6):1374-1378.
Stucky-Ropp RC, DiLorenzo TM. 1993. Determinants of exercise in children. Prev Med 22(6):880-889.
Sullivan SA, Birch LL. 1994. Infant dietary experience and acceptance of solid foods. Pediatrics 93(2):271-277.
Taggart AC, Taggart J, Siedentop D. 1986. Effects of a home-based activity program. A study with low fitness elementary school children. Behav Modif 10(4):487-507.
Trost SG, Pate RR, Saunders R, Ward DS, Dowda M, Felton G. 1997. A prospective study of the determinants of physical activity in rural fifth-grade children. Prev Med 26(2):257-263.
Trost SG, Pate RR, Ward DS, Saunders R, Riner W. 1999. Correlates of objectively measured physical activity in preadolescent youth. Am J Prev Med 17(2):120-126.
USDA. 2004. Food Guide Pyramid for Young Children. Washington, DC: USDA, CNPP. [Online]. Available: http://www.usda.gov/cnpp/KidsPyra/ [accessed April 15, 2004].
USDA (U.S. Department of Agriculture), DHHS (U.S. Department of Health and Human Services). 2000. Nutrition and Your Health: Dietary Guidelines for Americans. Home and Garden Bulletin No. 232, 5th ed. Washington, DC: Government Printing Office.
Wardle J, Cooke LJ, Gibson EL, Sapochnik M, Sheiham A, Lawson M. 2003. Increasing children’s acceptance of vegetables: A randomized trial of parent-led exposure. Appetite 40(2):155-162.
Weber Cullen K, Baranowski T, Rittenberry L, Cosart C, Owens E, Hebert D, de Moor C. 2000. Socioenvironmental influences on children’s fruit, juice and vegetable consumption as reported by parents: Reliability and validity of measures. Public Health Nutr 3(3):345-356.
Whitaker RC. 2004. Predicting preschooler obesity at birth: The role of maternal obesity in early pregnancy. Pediatrics 114(1):e29-36.
Whitaker RC, Pepe MS, Seidel KD, Wright JA, Knopp RH. 1998. Gestational diabetes and the risk of offspring obesity. Pediatrics 101(2):e9.
WHO (World Health Organization). 2003. Global Strategy for Infant and Young Child Feeding. Geneva: WHO.
Williams TM, Handford AG. 1986. Television and other leisure activities. In: Williams TM, ed. The Impact of Television: A Natural Experiment in Three Communities. Orlando, FL: Academic Press. Pp. 143-213.
Young-Hyman D, Herman LJ, Scott DL, Schlundt DG. 2000. Care giver perception of children’s obesity-related health risk: A study of African American families. Obes Res 8(3):241-248.
Zakarian JM, Hovell MF, Hofstetter CR, Sallis JF, Keating KJ. 1994. Correlates of vigorous exercise in a predominantly low SES and minority high school population. Prev Med 23(3):314-321.