Factors Shaping Food and Beverage Consumption of Children and Youth
Eating behaviors cannot be understood, explained, or changed without considering the context in which an individual lives (e.g., individual characteristics, home, and family). This context is nested within a broader community context, such as the neighborhood and schools, and societal factors (e.g., marketing, economics, culture). Interactions within and among these contexts affect behavior. A multidimensional approach to understanding the processes and context of the influences shaping children’s and youths’ eating behaviors can help explain relationships among factors in different domains.
This chapter presents an ecological perspective for understanding factors that influence child and adolescent eating behaviors and food and beverage choices. From this perspective, child and adolescent eating behaviors are conceptualized as a function of individual and environmental influences, or spheres of influence. These include biological factors, familial and social relationships, neighborhood, community, and institutional settings, culture and values, and broader social and economic trends. This chapter describes the following spheres of influence:
Individual and developmental factors (e.g., developmental, biological, psychological/psychosocial);
Family and social influences;
Institutional, neighborhood, and community environments; and
Macrosystem influences (e.g., marketing, culture and values, food systems).
All of these factors may directly or indirectly influence eating behaviors. If the diets of children and youth are to improve, attention must be given not only to the behavior of individuals but also to the environmental context and conditions in which people live and eat.
Current studies are inadequate to explain with certainty how individual and environmental influences interact to influence dietary behaviors and health outcomes of children and youth. Simultaneous analyses of sociodemographic, psychological, developmental, and environmental factors and their interactions with food choices are rare in the literature. The few cases that do exist are often focused on a specific age group or a single food group, such as fruits and vegetables. The following sections present both empirical evidence and theoretical links to eating behaviors.
INDIVIDUAL AND DEVELOPMENTAL FACTORS
Individual influences on children’s eating behaviors include biological and genetic factors, sensory characteristics, psychological and psychosocial factors, developmental stages, consumer socialization, and lifestyle factors.
Biological and Genetic Factors
Eating is a behavior influenced by physiological factors. It involves many organs and the central nervous system. Hunger, appetite, and satiety are all under neural regulatory control. Physiological factors influence food intake through sensory stimulation (e.g., smell, sight, taste of food), gastrointestinal signals, and circulating factors and chemical signals (e.g., glucose, insulin, peptides). Environmental and cognitive factors can interfere with or override physiological controls of eating and calorie intake. In fact, food intake in humans may depend more on external factors rather than physiological factors (Bell and Rolls, 2001).
Recent advances in the field of behavioral neuroscience have begun to increase the scientific understanding of the neurobiology of eating and food intake, including when and how much food is consumed and when eating is terminated. Gut–brain signals appear to be a critical neural network in the regulation of calorie intake and meal size. The discovery of bioactive food-stimulated gut peptides, adipocyte hormones, and hypothalamic neuropeptides all appear to affect food intake (Schwartz, 2004). It has been suggested that central regulatory mechanisms may contribute to the preference of sugars and fats over other macronutrients and tastes (Drewnowski and Levine, 2003). Much of the neurobiological mechanism research has been done in animal models, or human neuroimaging studies with patterns of
brain activation produced by the thought, sight, smell, or taste of food. Thus, the effect of the neurobiology of eating and food intake on human behavior has not been fully elucidated.
Some universal biological food predispositions may exist, including preferences for sweetness and fat texture, avoidance of irritation, avoidance of bitter and strong tastes, a tendency to be suspicious of new foods, and a set of genetic learning predispositions (Rozin, 2002). These predispositions may have served an adaptive function in human history when food was relatively scarce, modest in fat or sugar content, and limited in variety (Rozin, 2002). However, food today is abundant and widely available and thousands of new food products are introduced every year, including those high in sugar, fat, and salt, which appeal to our taste predispositions (Chapter 4). In today’s food environment, children’s predispositions and adults’ responses to them can promote food preferences and intake patterns that foster less healthful eating patterns that can contribute to the development of obesity (Birch, 1999).
Although the influences of genes on weight status and obesity are well documented, genetic influences on eating patterns and behaviors have received much less attention. While there is strong support from animal models for a genetic basis to food intake, a limited number of human studies suggest that food selection and intake, specifically for macronutrients (e.g., fats, carbohydrates) and total calories, may be genetically influenced to some extent (Keller et al., 2002). Research from family and twin studies suggests a modest to moderate genetic contribution to eating behaviors (de Castro and Plunkett, 2002; Keller et al., 2002; Klump et al., 2000; Reed et al., 1997). Selected adult twin studies show that heredity accounts for 11–65 percent of the variance in the average overall calorie intake (Keller et al., 2002). These studies also show the importance of nongenetic environmental effects. Studies among family members suggest that genetic influences on nutrient intake among first degree relatives is weak and that nongenetic effects associated with a shared environment are the major contributors to energy intake (Perusse et al., 1988). Studies assessing food preferences in both families and twins have found that the heritable component for individual foods is very low (Reed et al., 1997; Rozin and Millman, 1987). This suggests the important influential role of the environment on dietary patterns. Reported heritability of macronutrient intakes (e.g., fats, carbohydrates) tends to be somewhat stronger. A better understanding is needed to elucidate the complex interplay between human genes and the environment.
Individual variation in taste and food preferences may be genetically
influenced (Birch, 1999; Keller and Tepper, 2004). Sensitivity to bitter taste is a heritable trait. Compounds such as 6-n-propylthiouracil (PROP) taste bitter to some people and are tasteless to others. Some, but not all studies have shown that PROP tasters show lower acceptance of cruciferous and other bitter vegetables (e.g., broccoli, cabbage, brussel sprouts), have more food dislikes, and are more sensitive to sweet tastes and the texture of fat (Birch, 1999; Keller and Tepper, 2004). These studies suggest that genetic taste factors may play an important role in the development of food preferences and dietary intake in children (Keller et al., 2002). A better understanding of the genetic basis of taste may lead to the design of better dietary prevention strategies for children (Keller et al., 2002). More research is needed to identify genetic markers that will facilitate our understanding of genetic predispositions and how they interact with feeding and dietary experiences and social and environmental contexts.
Sensory Characteristics and Taste
Perceptions and responses to the sensory properties of food—taste, smell, and texture—affect food preferences and eating habits (Drewnowski, 1997). Sensory responses are influenced by genetic, physiological, and metabolic variables. Preferences for sweet tastes, saltiness, and fatty textures may be an innate human trait or acquired early in life. By about 4 months, for example, infants begin to show a preference for salt (Birch, 1999). On the other hand, bitter and strong tasting foods are often rejected early in life. From an evolutionary basis, these responses may have served biological functions needed for survival. In nature, sweetness is associated with readily available calories from carbohydrates, and salt is needed for survival. However, bitterness may be associated with natural toxins signaling dietary danger (Mennella et al., 2004, 2005; Rozin, 2002). The tendency to learn to prefer calorie-dense foods may have been adaptive at times in our history when food was scarce (Rozin, 2002).
Innate taste responses are observed immediately after birth. Facial expressions on human newborns show a positive hedonic response to sweet tastes and a negative response to bitter and sour tastes (Drewnowski, 1997). The sensory pleasure response to sweetness and dietary fat may be mediated by the brain through neurotransmitters or endogenous opiate peptides (Benton, 2004).
Studies of young children have shown that their food preferences are influenced primarily by two factors: sweetness and familiarity (Birch, 1999; Drewnowski, 1997). Preferences for fat also may be acquired in early life, as children learn to prefer those flavors of foods that are associated with
high-calorie and fat content (Drewnowski, 1997). However, the predisposition to prefer a sweet taste is readily modified by experiences with food and eating (Birch, 1999). One study showed that at birth all infants preferred sweet solutions to water, but by 6 months, preference for sweetened water was linked to the infant’s food experience; those infants routinely given sweetened water by their mothers showed a greater preference for it than infants who had been given water that was not sweetened (Beauchamp and Moran, 1982). Substantial evidence shows that predispositions to prefer sweet, fatty, and salty foods and reject bitter ones can be readily altered through experience with food and eating (Birch, 1999).
Flavor is another primary dimension by which young children determine food acceptance (Mennella et al., 2005). Some relatively new evidence has hypothesized that experience with a flavor in amniotic fluid or breast milk may modify an infant’s acceptance and enjoyment of similarly flavored foods at weaning, and that this may underlie individual differences in food acceptability and possibly serve as the foundation for lifelong food habits (Mennella et al., 2004). Mennella et al. (2001) found that weaning infants who had exposure to the flavor of carrots in either amniotic fluid or breast milk were perceived to respond more positively to that flavor in a food base than did nonexposed infants. Thus, preliminary research suggests that prenatal and early postnatal exposure to flavors may predispose the young infant to have a favorable response to those flavors in foods.
One of the most important individual influences on food choice is taste, which also is influenced by the aroma and texture of food. Research has consistently shown that children, adolescents, and adults all report that taste is the most important influence on their food choices (Barr, 1994; French et al., 1999; Glanz et al., 1998; Horacek and Betts, 1998; Neumark-Sztainer et al., 1999). Taste preference has also been found to be directly related to children’s fruit and vegetable consumption (Neumark-Sztainer et al., 2003), calcium intake (Barr, 1994), and carbonated soft drink consumption (Grimm et al., 2004). In studies assessing motivation for vending snack choices and food choices at school, adolescents rated taste as the most important factor to consider, followed by hunger and price (French et al., 1999; Shannon et al., 2002). Those who placed greater emphasis on snack taste were less likely to report low-fat vending snacks as current or intended choices. “Healthfulness” and “tastiness” tend to be seen as opposites by children (Wardle and Huon, 2000).
There appears to be widespread belief among children and adolescents that “if a food tastes good, it must not be good for me” and “if a food tastes bad, it is probably good for me” (Baranowski et al., 1993). In one study of
teenagers, only one-fourth thought low-fat foods taste good (Shannon et al., 2002). In an experimental study with 9- to 11-year-old children, Wardle and Huon (2000) tested the idea that a “healthy” label would reduce the appeal of a novel drink. Children were asked to taste and rate one or two drinks—one was described and labeled as “a new health drink” and the other as a “new drink.” The results showed children rated the drink labeled healthful as tasting less pleasant and said they would be less likely to ask their parents to buy it than the same drink presented just as a “new drink” (Wardle and Huon, 2000).
Early childhood lays the foundation for food behaviors and food preferences. The developmental stage1 of a child has a central influence on eating behaviors. During infancy (ages 0–12 months), feeding is central to the parent–child relationship and for the infant developing a sense of security and trust. Early childhood (ages 1–5 years) is characterized by rapid growth and change in the child’s physical, cognitive, communicative, and social development (NRC and IOM, 2000). Eating behaviors move from complete dependence on the caregiver to more self-directed control. During early childhood, parents and primary caretakers largely determine what foods are provided and when eating occurs. Developmental characteristics of young children influence their eating behavior and include dislike for new foods (neophobia), food jags (favoring only one or two foods), and picky eating (e.g., refusal to eat certain foods and not wanting foods to touch each other on the plate) (Story et al., 2002a). These are normative behaviors in young children (Birch, 1999).
Middle childhood (ages 6–11 years) is a time of major cognitive development and mastery of cognitive, physical, and social skills. Children in this age group progress from dependence on their parents to increasing independence, with a growing interest on the development of friendships and the world around them. Their eating behaviors reflect these changes and become more influenced by outside sources.
The dramatic physical, developmental, and social changes that occur during adolescence (ages 12–19 years) can markedly affect eating behaviors and dietary intake. Growing independence and eating away from home, concern with appearance and body weight, the need for peer acceptance, and busy schedules all can impact eating patterns and food choices.
In this report, the committee characterized infants and toddlers as under age 2 years, younger children as ages 2–5 years, older children as ages 6–11 years, and teens as ages 12–18 (Chapter 1). These age categories and terms differ slightly from what is presented from the research described in this chapter.
Age-associated declines in diet quality are evident as children move from childhood through adolescence. For example, a recent longitudinal study with girls found that dietary quality declined between ages 5 and 9 years (Mannino et al., 2004). Girls at 9 years of age tended to have inadequate intakes of dairy foods, fruits and vegetables, and several nutrients more often than the younger girls. Other longitudinal studies have shown that dietary decline continues during middle childhood into adolescence; intakes of fruits, vegetables, and milk decreases, and carbonated soft drinks increase (Lytle et al., 2000).
Psychological and Psychosocial Factors
The complex interactions of many factors shape food preferences, including a child’s early experiences with food and eating, positive or negative conditioning, exposure, and genetics (Birch, 1999). Self-reported food preferences are one of the strongest predictors of food choices and dietary intake (Baranowski et al., 2002; Birch and Fisher, 1998; Drewnowski and Hann, 1999; Woodward et al., 1996). Repeated exposures increase children’s preference for a food or flavor (Birch, 1999). A longitudinal study of children from ages 2–3 years to 8 years reported that a high percentage of children’s food preferences are formed as early as ages 2–3 years, and few changes in preferences occurred over the 5-year period (Skinner et al., 2002). The strongest predictors of the number of foods liked at age 8 years were the number of foods liked at age 4 years (Skinner et al., 2002).
When food is plentiful, food likes and dislikes play an important role in influencing food choices. Among children, sweet foods and high-fat foods tend to be the most preferred foods (Drewnowski, 1997; Rozin, 2002), while vegetables are the least preferred foods (Skinner et al., 2002). Parents often cite dislike as the primary reason for children’s low vegetable intakes (Wardle et al., 2003a). It is not clear why vegetables are disliked by children, but it may be because of the sensitivity to the bitter taste of cruciferous vegetables, bland preparation of vegetables, the negative context in which vegetables may be presented—if you want dessert, you have to eat your peas, poor parental modeling, or low exposure. Skinner et al. (2002) found that foods disliked by mothers tended not to be offered to children. A growing body of research suggests that a dislike of foods can be transformed into liking with experience of repeated tasting or exposures (Wardle et al., 2003a). In one study with children, 10 daily exposures to the taste of an unfamiliar vegetable (e.g., raw red pepper) significantly increased children’s liking and consumption of the vegetable (Wardle et al., 2003b). Another recent study found that daily exposure for 14 days to the taste of a
previously disliked vegetable increased children’s (ages 2–6 years) liking and consumption of that vegetable (Wardle et al., 2003a). These results suggest that repeated exposure through frequent tasting may be effective in increasing children’s acceptance of vegetables and other healthful, but not necessarily well-liked foods (e.g., whole grains, unsweetened cereals). In homes, schools, and child-care settings, repeated exposure to initially disliked foods in an emotionally positive atmosphere could increase preference and consumption of those foods.
Social factors and the context in which the food is offered are important in shaping children’s preferences. Preschool children’s preferences for and consumption of disliked vegetables increased when children observed peers choosing and eating the vegetables that the target child disliked (Birch, 1999). Child feeding practices may also impact children’s preferences and intake patterns. When children are given foods as rewards for approved behaviors, enhanced preference for those foods results (Birch, 1999). In contrast, when children are rewarded for eating a disliked food such as vegetables, this leads to a decline in the preference for that food (Birch, 1999).
Finding: Food preferences develop as early as 2–3 years of age and are shaped by a child’s early experiences, positive or negative conditioning, exposure to foods, and a biological predisposition to prefer sweet, high-fat, and salty foods.
Gender differences in food choices and dietary intakes emerge as children move into adolescence. During childhood food intakes are similar between girls and boys. U.S. Department of Agriculture (USDA) data from the 1989–1991 Continuing Surveys of Food Intakes by Individuals (CSFII) showed little differences in mean daily intakes of the Food Guide Pyramid groups for grains, vegetables, fruit, dairy, and meat among boys and girls ages 2–5 years and ages 6–11 years (Munoz et al., 1997). Among adolescents, boys ate more servings of grains, more vegetables (including french fries), dairy, and meat servings compared to girls (Chapter 2).
Studies have shown that as a group, adolescent girls are more likely than adolescent boys to have lower intakes of essential vitamins and minerals, and fewer servings of fruits, vegetables, and dairy foods (Gleason and Suitor, 2001; Story et al., 2002b). Boys are more likely to have diets higher in total fat and saturated fat compared to girls (Gleason and Suitor, 2001; Troiano et al., 2000) and to consume larger amounts of carbonated soft drinks (French et al., 2003a). On average, adolescent boys eat larger quantities of food than adolescent girls, so they are more likely to meet daily
recommended intakes for vitamins and minerals. Adolescent girls are also more likely to skip meals, especially breakfast, than are adolescent males (Gleason and Suitor, 2001; Chapter 2).
Gender differences in attitudes towards food are also evident during adolescence. Adolescent girls are more likely than adolescent boys to be concerned about health and weight, and this concern is associated with more positive attitudes and behaviors regarding healthful foods. In one study of 1,083 adolescent high school students, girls were more likely than boys to report that low-fat foods are beneficial for future health and maintaining weight (Fulkerson et al., 2004a). Boys were more likely than girls to report that healthful eating is not important to them. Girls’ weight concerns may predispose them to have more favorable attitudes toward healthful eating. These results suggest the importance of segmented nutrition education interventions for adolescents.
Concern About Health and Nutrition
Health and nutrition are not a primary influence on the food choices among the majority of children, adolescents, and adults. In a study of 289 adolescents, while nearly two-thirds (61 percent) of the students reported that eating healthful foods was important to them, only 27 percent were motivated by health in making food choices (Shannon et al., 2002). Gender differences are also evident; one-third (36 percent) of girls report being motivated by health concerns compared to only 18 percent of adolescent boys (Shannon et al., 2002). Studies have also shown that students with higher health concerns have lower intakes of fat and higher nutrient intakes compared to those less concerned about health (Horacek and Betts, 1998). Conversely, those least motivated by health concerns had the highest fat intakes. Other studies have shown that children who value health for the foods they choose have better dietary quality (Gibson et al., 1998). Research has demonstrated that age positively predicts the perceived importance of nutrition and the health effects of food; it becomes more important as people age and is most valued by older adults (Glanz et al., 1998).
From a developmental perspective, it is not surprising that health and nutrition are low-priority concerns for adolescents, that adolescents are the most inclined toward eating behaviors that are incompatible with a healthful diet, and that they are less concerned about nutrition compared to their parents or grandparents (Rozin, 2002). Qualitative research has shown that many adolescents do not perceive a need or urgency to change their eating behavior when the future seems so far away (Neumark-Sztainer et al., 1999; Story and Resnick, 1986). For many, the long-term benefits of good health may not outweigh the short-term advantages of convenience and immediate gratification.
Although knowing how and why to eat healthfully is important, nutrition knowledge alone does not ensure that children or adolescents will adopt healthful eating behaviors. A meta-analysis of the literature with adults, adolescents, and children found the association of nutrition knowledge with dietary behavior to be very weak (r = 0.10) (Axelson et al., 1985). Another more recent study with adults using CSFII data found that adults with more nutrition knowledge consumed more fruit and vegetables (Guthrie et al., 2005). Another study with mothers and children ages 9–11 years found that mothers’ nutrition knowledge was strongly correlated to their children’s fruit intake, but not to their intake of vegetables or sweets (Gibson et al., 1998). Children’s own nutrition knowledge did not correlate with their fruit or vegetable intake (Gibson et al., 1998). Clearly, nutrition knowledge alone is not sufficient to change dietary behaviors.
Stress and Depression
Stress and depression can affect appetite through either an increase or decrease in eating. However, relatively little research has been done with children or adolescents. Cartwright et al. (2003) examined associations between psychological stress and dietary practices in a socioeconomically and ethnically diverse sample of 4,320 children ages 11–12 years. Children completed a Perceived Stress Scale and food frequency questionnaires. Greater stress was associated with eating higher-fat foods, less fruit and vegetable intake, more frequent snacking, and skipping breakfast. These effects were independent of gender, weight, socioeconomic status, and ethnicity.
An extensive body of research supports a strong relationship between depression and eating disorders among adolescents, as well as depression and weight dissatisfaction, negative body image, and disordered eating behaviors (Fulkerson et al., 2004b). Less is known about childhood depression and dietary practices. In a survey of 4,734 ethnically diverse middle and high school students, Fulkerson et al. (2004b) found that depressive symptoms were positively associated with perceived barriers to healthful eating and weight concerns. Adolescents who reported more depressive symptoms were less likely to eat breakfast, lunch, and dinner. No association was seen between depressive symptoms and calorie or nutrient intakes.
Dieting is a widespread practice among preadolescents and adolescents, especially girls. Nationwide in 2003, 59 percent of high school girls
and 29 percent of high school boys reported trying to lose weight during the 30 days preceding a survey conducted by Grunbaum et al. (2004). Nearly 20 percent of girls had gone without eating for 24 hours or more to lose weight, 11 percent had taken diet pills to lose weight, and 8 percent had vomited or taken laxatives to lose weight during the past 30 days (Grunbaum et al., 2004). The few studies that have examined adolescent weight control behaviors and associations with dietary intakes have had inconsistent results (Barr, 1995; French et al., 1995; Neumark-Sztainer et al., 2000; Story et al., 1998). Studies have shown that adolescents who engage in less healthful weight control behaviors (e.g., vomiting, laxatives, or diet pills) are at increased risk for dietary inadequacy and weight gain (Neumark-Sztainer et al., 2004; Story et al., 1998). Among 4,144 adolescents, girls using less healthful weight control behaviors had significantly lower intakes of fruits and vegetables, grains, calcium, iron, and other micronutrients compared to girls using healthy weight control methods or not dieting (Neumark-Sztainer et al., 2004). No such relationship was found among boys.
Several controlled laboratory and naturalistic studies show that in the short-term, older children and adults eat more with increasing portion sizes and larger package sizes (Rolls, 2003). In a laboratory study (Rolls et al., 2000), 5-year-old children varied their intake at meals directly with changes in portion sizes. When offered larger portions, children ate substantially more. In the same study, young children (about 3.5 years old) did not vary intake in relation to changes in portion size, suggesting that the ability to respond to internal cues of hunger is stronger at younger ages and diminishes with age as external factors become increasingly influential.
Food packaging and portion sizes have increased steadily over the past 30 years (Wansink, 2004; Young and Nestle, 2002). Data suggest that the trend toward larger portion sizes began in the 1970s, increased sharply in the 1980s, and has continued to increase (Young and Nestle, 2002). Package size influences the volume of food consumed. When food packages are doubled in size, consumption in adults generally increases by 18–25 percent for meal-related foods and 30–45 percent for snack-related foods (Wansink, 2004). Data indicate that away-from-home portions sizes have increased over time (Nielsen and Popkin, 2003; Young and Nestle, 2002; Chapter 2). Larger portions not only contain more calories but also encourage people to eat more. Research suggests that individuals tend to overconsume high energy-dense foods beyond physiological satiety (Kral et al., 2004), especially when they are unaware that the portion sizes served to them have been substantially increased (Rolls et al., 2004). Satiety signals are not
triggered as effectively with high energy-dense foods (Drewnowski, 1998), and large portions of them consumed on a regular basis are particularly problematic for achieving energy balance and weight management in older children and adults.
In contrast to 15–25 years ago, quick serve restaurants and full serve restaurants use larger portion sizes in their marketing promotions. Restaurants are using larger dinner plates and quick serve restaurants are using larger containers for drinks and french fries (Young and Nestle, 2002). In an analysis, Young and Nestle (2002) found that the containers for virtually all foods and beverages prepared for immediate consumption have increased over time and now appear to be typical and the norm. Given these findings, there is a need for greater attention to food portion size and consuming recommended serving sizes, such as those in the Dietary Guidelines for Americans (DHHS and USDA, 2005).
Finding: The availability and marketing of foods and beverages of larger portion sizes has increased steadily over the past three decades in many venues.
Consumer Socialization and Behavior
Consumer socialization refers to the “processes by which children and adolescents acquire skills, knowledge, and attitudes relevant to their functioning as consumers in the marketplace” (Ward, 1974). Consumer socialization occurs in the context of cognitive, social and developmental changes as children progress through childhood and adolescence and become socialized into their roles as consumers. Over the past 25 years, a large body of consumer research has accumulated on children’s knowledge of products, brands, advertising, pricing, shopping skills, decision-making skills and abilities, parental influence and negotiation approaches, and social aspects of the child consumer role. American children are avid consumers and become socialized into this role from an early age (John, 1999). Children’s consumer socialization and behavior influences food choices, both by direct purchases and by the substantial influence children have on family purchases.
A child’s first request for a product occurs at about 24 months, and 75 percent of the time, this request occurs in a supermarket. McNeal (1999) found that the most common first in-store request is ready-to-eat breakfast cereal (47 percent), followed by snacks (30 percent), and toys (21 percent). Requests are often made for a branded product. Isler et al. (1987) examined the location, types, and frequency of products that children ages 3–11 years requested of their mothers over 30 days. Food accounted for more than half (55 percent) of total requests made by children and included snack and
dessert foods (24 percent), candy (17 percent), cereal (7 percent), quick serve restaurant foods (4 percent), and fruit and vegetables (3 percent) (Isler et al., 1987). Nearly two-thirds (65 percent) of all cereal requests were for presweetened breakfast cereals. Research indicates that parents honor children’s requests for food about half of the time: carbonated soft drinks (60 percent), cookies (50 percent), and candy (45 percent) (McNeal, 1999). Dual-income families may be more likely to accommodate children’s purchase requests (McNeal, 1999).
Adolescents also have a strong influence on grocery store purchases. In one national market research study, more than 60 percent of adolescents reported that they influence their parents’ purchase of fast foods (65 percent), pizza (63 percent), and carbonated soft drinks (60 percent) (Zollo, 1999; Chapter 4). Adolescents also shop for the family groceries. A recent study with 4,746 youth found that more than half (52 percent) of adolescent girls and boys do some food shopping each week for their family (Hanson et al., 2006). Girls, younger adolescents, youth from low-income families, and ethnic minority youth were more likely to report assisting their parents with food shopping.
Parents acknowledge the influence that children have on their food purchases. In a national market survey of 930 adult family meal planners, 38 percent of parents reported that children always or often dominate dinner grocery decisions, 52 percent said they sometimes influence dinner grocery decisions, and only 10 percent reported that their children never have an influence (National Pork Producers Council, 2000). Parents reported that their children always or often influenced grocery purchase decisions for snacks (75 percent), breakfast foods (72 percent), desserts (47 percent), and dinner (38 percent) (Chapter 4). Another market study on consumer decision-making found that parents are two to three times more likely to name a child rather than themselves, as the family expert for selection of fast foods, snack foods, and new breakfast cereals (USA Weekend and The Roper Organization, 1989).
Children’s consumer socialization research has also examined brand awareness. Children as young as ages 2–3 years can recognize familiar packages in the stores and familiar spokescharacters on products such as food, toys, and clothing (John, 1999). By preschool, children begin to recall brand names from seeing them advertised on television or featured on product packages, especially if the brand names are associated with salient cues such as cartoon spokescharacters, colors (e.g., packages), or pictures (John, 1999). Brand awareness develops first for child-oriented product categories such as cereals, snacks, and toys. By the time they enter the first grade children are familiar with roughly 200 brands, the average 10-year-old recognizes 300–400 brands, and an adult recognizes about 1,500 brands (McNeal, 1999). When children make requests for foods at the supermar-
ket, more than 90 percent are by brand name and of these, 82 percent are for national brands (McNeal, 1999).
Although brand choice can be important to teenagers, they are likely to experiment with numerous brands. Teens are much more brand loyal when buying personal-hygiene products than when buying food or apparel. Of food products, carbonated soft drinks and quick serve restaurants have the highest brand loyalty among teenagers (Zollo, 1999). Because of this fact, many food and beverage marketers have intensified their efforts to develop brand relationships with young consumers (Zollo, 1999; Chapter 4). The marketing literature clearly emphasizes that in order to develop brand loyalty, marketing must start with young children (McNeal, 1999; Chapter 4).
Finding: Children are aware of food brands as young as 2–3 years of age and preschoolers demonstrate brand recognition when cued by spokescharacters and colored packages. The majority of children’s food requests are for branded products. Brand loyalty is highest in teens for carbonated soft drinks and quick serve restaurants.
Time and Convenience
Perceived time constraints and convenience strongly influence the food choices of children, adolescents, and adults (Glanz et al., 1998; Neumark-Sztainer et al., 1999). In focus groups with adolescents from low-income families in California, convenience was a major driving factor in determining food choices (California Project LEAN and Food on the Run Campaign, 1998). In another study using focus groups, adolescents discussed wanting to sleep longer in the morning instead of taking the time to eat or prepare breakfast, not wanting to wait in a long lunch line, eating at quick serve restaurants because the food is served quickly, and choosing foods at home that can be prepared quickly (Neumark-Sztainer et al., 1999). Lack of time is also perceived as a major barrier to eating more healthfully. Adolescents often believe they are too busy to worry about food and eating well. Common remarks were “People our age are so busy that we don’t have enough time to change bad habits” and “We don’t have the time … too many pressures” (Story and Resnick, 1986).
Cost of Food
Studies of adults have found that taste is considered to be the most important influence on food selection, followed by cost (Glanz et al., 1998). Adolescents also appear to be price sensitive (California Project LEAN and
Food on the Run Campaign, 1998; French et al., 1997a,b, 1999, 2001a; Neumark-Sztainer et al., 1999). In one study, adolescents rated cost as the third most important reason in selecting vending snacks after taste and hunger (French et al., 1999).
Several studies have empirically demonstrated large effects of price reduction on sales of fresh fruits and vegetables and lower fat vending snacks in high school settings (French et al., 1997a,b, 2001a). A 50 percent price reduction on fresh fruit and vegetables increased weekly sales two- to four-fold during a 3-week period in two high school cafeteria a la carte areas (French et al., 1997b). In a large study involving 12 high schools and 12 worksites, price reductions on low-fat vending machine snacks of 10, 25, and 50 percent, increased sales of these items by 9 percent, 39 percent, and 93 percent, respectively (French et al., 2001a). The results of these studies clearly show the powerful effect of price on adolescent’s food choices.
FAMILY AND SOCIAL INFLUENCES
Children’s and adolescents’ eating behaviors are strongly influenced by their social environments, especially the home and family environment. Interpersonal influences can affect eating behaviors through mechanisms such as food availability, modeling, reinforcement, social support, and perceived norms.
The family is a major influence on children’s and adolescents’ eating behavior and dietary intake. The family mediates dietary patterns in three primary ways: (1) the family is a provider of the foods that are available and accessible in the home; (2) the family provides the meal structure, when meals occur, and what is offered; and (3) the family transmits food attitudes, food preferences, brand preferences, and values that may affect lifetime eating habits. The home is where the majority of eating occasions and calorie intake occur for both children and adolescents. National CSFII 1994–1996 data indicate that children and adolescents ages 2–19 years consumed 70 percent of their meals and 80 percent of their snacks at home and obtained 68 percent of total calories from home (Lin et al., 1999). Younger children were more likely to eat meals and snacks at home and obtain a greater proportion of calories at home compared to adolescents; for children ages 2–5 years, 76 percent of total daily calories were eaten at home compared to 67 percent for youth ages 6–11 years and 65 percent for adolescents ages 12–19 years (Lin et al., 1999; Chapter 2).
American families have undergone profound social changes in family structure and maternal employment over the past 40 years. In 1960, only 9 percent of children lived in single-parent households. In 2004, 28 percent of children lived in single-parent households, and the majority of those parents were mothers (U.S. Census Bureau, 2005). Also, maternal employment has grown significantly in the past 30 years. From 1970 to 2000, the overall maternal labor-force participation rate rose from 38 to 68 percent (NRC and IOM, 2003). A 2003 study showed that 60 percent of mothers with preschool children (younger than age 6 years) and 75 percent of mothers with children ages 6–17 years were employed in the U.S. labor force (DHHS, 2003). Of these employed mothers, 70 and 78 percent work full-time and part-time, respectively (DHHS, 2003). Trends of fewer family meals, the increasing popularity of fast food and eating out, and the increased demand for convenience and prepared foods are likely related to shifts in family composition and work schedules. Family food preparation traditionally has been largely the work of women, and although more of them are working outside of the home, they continue to have the greatest responsibility for home food production (Harnack et al., 1998).
Few studies have investigated the relationship between mothers’ work status and children’s diets. Studies using data from the late 1980s found that maternal employment had no significant effect on the quality of the diets of preschool children (Johnson et al., 1992, 1993). A recent study explored the effects of mothers’ work on their children’s nutritional status using CSFII data from 1994–1996 and 1998 (Crepinsek and Burstein, 2004). Children ages 1–17 years with full-time working mothers had lower overall Healthy Eating Index (HEI) scores (indicative of poorer diet quality), lower intakes of iron and fiber, and higher intakes of carbonated soft drinks and fried potatoes, and were more likely to skip morning meals than children of nonworking mothers. Working mothers were also more likely to rely on away-from-home food sources. These differences remained after controlling for family household characteristics, such as income and the number of adults in the household. Children whose mothers worked part-time had more positive eating patterns than those whose mothers worked full-time (Crepinsek and Burstein, 2004).
A recent study assessed the effect of maternal employment on childhood obesity using matched mother–child data from the National Longitudinal Survey of Youth (Anderson et al., 2003). The results indicate that the more hours the mother worked per week, the more likely a child was to be obese. Analyses by subgroups showed that higher socioeconomic status mothers who worked more hours per week over the child’s life were the most likely to have an obese child. Potential mechanisms through which
children’s eating patterns and physical activity may be affected by working parents include less time to prepare family meals, more reliance on eating out or buying fast foods for consumption at home, and less supervision, which may lead to children preparing high-calorie and low-nutrient foods and beverages after school or spending more time indoors (Anderson et al., 2003).
Household Socioeconomic Status
In 2003, 11.6 million, or 16 percent, of children under the age of 18 years lived in families with incomes below the federal poverty level (Federal Interagency Forum on Child and Family Statistics, 2004). Evidence shows that dietary intakes and dietary patterns in families vary depending on economic circumstances. A recent study analyzed 24-hour recall data from the National Health and Nutrition Examination Survey III (1988–1994) (Fox and Cole, 2004). Three groups of children (ages 5–18 years) were compared based on household income: income at or below 130 percent of poverty (lowest income), income between 131 and 185 percent of poverty (low income), and income above 185 percent of poverty (higher income). Children in the lowest income group were more likely than children in the higher income group to have consumed fewer than three meals in the preceding 2 days (39 percent versus 34 percent) and were less likely to eat breakfast every day (44 percent versus 48 percent). Overall, there were no differences between income groups in mean usual calorie intake. However, children in the lowest income group obtained a greater percentage of calories from fat compared to the higher income group. There were no significant differences among income groups on mean HEI scores; the diets of 78 percent of all children showed a need for improvement, and only 6 percent of children had “good” diets (Cole and Fox, 2004; Chapter 2).
Other studies have found socioeconomic status effects. National data from the CSFII 1989–1991 data found that lower calorie intakes were found among children from less affluent households. In addition, children from lower income households were less likely to meet the recommendations for fruit and dairy intakes (Munoz et al., 1997). Other studies have also shown socioeconomic status differences. Adolescents in lower income households were more likely to consume insufficient fruits and vegetables (Lowry et al., 1996; Neumark-Sztainer et al., 1996). The National Growth and Health Study with 9- to 10-year-old girls found that percentage of calories from fat was inversely related to family income and parental education levels (Crawford et al., 1995). However, food insecurity has not been clearly associated with obesity in children or adolescents with the exception of white adolescent girls (Chapter 2).
Food costs may be one barrier to the adoption of healthier diets, espe-
cially by low-income households. Calorie-dense foods, some of which are high in refined grains, added sugars and added fat, provide calories at a far lower cost than do lean meats, fish, and fresh vegetables and fruits (Drewnowski, 2004). Surprisingly, there are little data on what it costs to eat a healthful diet in the United States. A recent USDA analysis estimated an annual retail price per pound for 69 types of fruits and 85 types of vegetables (Reed et al., 2004). More than half of the fruits and vegetables were estimated to cost 25 cents or less per serving. It was estimated that three servings of fruits and four servings of vegetables would cost only 64 cents per day. After adjusting for waste and serving size, 63 percent of fruits and 57 percent of vegetables were least expensive in their fresh form (Reed et al., 2004). Based on this study, it appears that consuming fresh fruits and vegetables may be very affordable. More studies need to be conducted on the costs and perceived trade-offs of eating a healthful diet.
Household food availability and accessibility have been identified as strong correlates of food intake in children and adolescents. Availability refers to whether foods are present in the home, and accessibility refers to whether these are available in a form, location, or time that facilitates their consumption, such as precut vegetables in a plastic bag on a front shelf in the refrigerator or a bowl of fruit on a table (Cullen et al., 2003). Using structural equation modeling, Neumark-Sztainer et al. (2003) found that the strongest correlates of fruit and vegetable intake among adolescents were home availability of fruits and vegetables and taste preferences. Home availability was mediated by parental social support for healthful eating, family meal patterns, and household food security (access to an affordable food supply). Even when taste preferences for fruits and vegetables were low, if fruits and vegetables were available in a household, intakes increased. Availability of carbonated soft drinks in the home has also been found to be strongly associated with carbonated soft drink consumption among 8- to 13-year-olds (Grimm et al., 2004).
Recent studies suggest that family meals exert a strong influence on the dietary intake of children and adolescents. Three large population-based studies have all found that increasing the frequency of family meals is associated with more healthful dietary intake patterns in children (Gillman et al., 2000; Neumark-Sztainer et al., 2003; Videon and Manning, 2003).
Increasing the frequency of family dinner has been associated among children ages 9–14 years with consumption of more fruits and vegetables;
less fried foods and carbonated soft drinks; less saturated fats and trans fat; more fiber, calcium, folate, and iron; and more vitamins B6, B12, C, and E (Gillman et al., 2000). The frequency of family meals and associations with dietary intake were also examined in 4,746 middle and high school students (Videon and Manning, 2003). Frequency of family meals was associated positively with intakes of several vitamins and minerals, fruits, vegetables, grains, and calcium-rich foods.
Parental diet has been shown to be a strong predictor of children’s intake in several studies. The strongest predictor of 2- to 6-year-old children’s fruit and vegetable consumption was parental fruit and vegetable consumption (Cooke et al., 2003; Wardle et al., 2005). In another study, 8- to 13-year-old youth whose parents regularly consumed carbonated soft drinks were nearly three times more likely to consume carbonated soft drinks five or more times a week compared with those whose parents did not regularly consume carbonated soft drinks (Grimm et al., 2004). One study found mother–daughter similarities in milk and carbonated soft drinks consumption (Fisher et al., 2000) and in fruit and vegetable intake (Fisher et al., 2002). In another study of adolescents, parental intakes were positively associated with intake of fruits, vegetables, and dairy products in girls and dairy products in boys (Hanson et al., 2005).
The relationship between parent and child intake may be due to a combination of factors including role modeling effects, food availability in the home, or genetic influences (Birch, 1999; Cooke et al., 2003; Neumark-Sztainer et al., 2003). As mentioned earlier, genetic influences on food preferences and intakes among family members are weak. There is evidence that supports the influence of parental role modeling on children’s eating behaviors (Brown and Ogden, 2004). This influence may be direct through what parents actually eat or indirect through transmission of eating-related attitudes. The influence of parental role modeling on children’s eating is consistent with Social Learning Theory (Bandura, 1977) and the importance of observational learning and modeling (Brown and Ogden, 2004). These findings suggest the importance of making parents and caregivers aware of the critical role they play in children developing healthful eating behaviors. Parents and caregivers can act as role models to encourage the tasting of new foods and model healthful eating behaviors.
Child Feeding Practices
Another factor that may influence a child’s food preference and dietary intake is child feeding practices used by parents. In a series of experimental
studies with young children, feeding practices commonly used by parents—such as restricting foods considered to be less nutritious, pressuring children to eat, or using foods as rewards—have been shown to inadvertently promote behaviors counter to their intentions (Birch, 1999; Birch and Fisher, 1998). For example, restricting access to palatable foods promotes children’s preference for and intake of these “forbidden foods” (Birch, 1999). Forcing or pressuring children to eat certain foods decreases the preference for that food (Birch, 1999). Rewarding children for eating a disliked food (e.g., vegetables) led to a decline in the preference of that food. On the other hand, if children are given both sweet and nonsweet foods as rewards for approved behavior, the preference for those foods is enhanced. In American society, high-fat and sweet food items are used repeatedly in positive child contexts for rewards, treats, and celebrations, thus further reinforcing the preference for these foods. Birch (1999) also found that when children were offered food items that were initially neither liked nor disliked, but were then used as rewards or associated with positive parental attention, the preference for these foods increased. This has implications for child feeding strategies; for example, using vegetables such as carrots as rewards for young children.
Children and adolescents spend a substantial amount of time with their peers and friends through child-care or school settings, after-school programs, sports activities, or recreation time. The social influence of the peer group affecting food preferences and food choices is not well explored, and the few studies done have not found consistent results. Birch (1999) found that preschool children began to like and eat certain vegetables they previously disliked when they saw their peers eating those foods. This reinforces the importance of peer modeling and observational learning.
Feunekes et al. (1998) examined resemblances in high-fat foods and food intakes within social networks of adolescents, their closest friends, and their parents. Although there were significant associations between parent and adolescent intakes (76–87 percent of the items on the food frequency), only 19 percent of the foods were correlated for adolescents and their friends. These tended to be for snack foods. A recent study examined the resemblances in food preferences between good friends in three third-grade classrooms (Rozin et al., 2004). They found that friendship had no effect on food preferences. It may be that preferences are mediated through role modeling and that a major social influence on food preferences is the preferences of an admired child who is older or media role models (Rozin et al., 2004). Social influences on food intake and the modeling of eating behaviors of admired peers, older youth, and media or
celebrity role models need to be explored. Such effects would have implications for designing interventions to improve eating behaviors of children and adolescents.
INSTITUTIONAL, NEIGHBORHOOD, AND COMMUNITY INFLUENCES
Child care is now the norm for American children. Approximately 80 percent of children ages 5 years and younger with employed mothers are in a child-care arrangement for an average of almost 40 hours per week, and 63 percent of children ages 6–14 years spend an average of 21 hours per week in the care of someone other than a parent before and after school (NRC and IOM, 2003). Nationwide, 32 percent of young children receive center-based care, 16 percent are in family child care, and 6 percent are cared for by a nanny or babysitter in the child’s home (Capizzano et al., 2000). Children in full-time child care can receive up to two meals and snacks per day through federal meal programs.
The Child and Adult Care Food Program (CACFP) is a federal program providing meals and snacks to lower income children in child-care centers, the Head Start Program, family child-care homes, and after-school programs. The program serves an average of 2.9 million children per day and provides roughly 1.7 billion meals and snacks to children annually (FRAC, 2005). Child- and adult-care providers who participate in CACFP are reimbursed at fixed rates for each meal and snack served. Given that children in full-time child care could receive up to two meals and snacks per day through these programs, child-care settings could have a substantial impact on children’s dietary intakes. However, there is little research that has assessed the nutritional quality of foods in child-care settings. Few data are available about the types and quantities of foods and snacks served to children in child-care settings and their impact on dietary intake. The USDA has established minimum requirements for the meals and snacks offered by participating child-care providers, but they are not required to meet specific nutrient-based standards such as those required for the National School Lunch Program (NSLP) and School Breakfast Program (SBP). Research is also scarce on the impact that the CACFP program has on participants’ dietary intakes, and the limited amount of research that is available is not descriptive. A national study on CACFP-participating child-care sites found that the meals and snacks provided 61–71 percent of children’s daily energy needs and more than two-thirds of the Recommended Dietary Allowance (RDA) for key nutrients. Meals and snacks exceeded the Dietary Guidelines for Americans for saturated fat (Fox et al., 1997).
Furthermore, there is a child-care system that extends beyond CACFP and includes formal and informal care of children outside of the home. All of these child-care settings have the potential to influence the diets of children but, as with CACFP, there is limited research on the dietary intake of children in these settings.
The school food environment can have a large impact on children’s and adolescents’ dietary intake. National data show that foods eaten from the school cafeteria comprise 19–50 percent of students’ total daily calorie intake during a school day (Burghardt et al., 1993; Gleason and Suitor, 2001).
Nearly all public schools and 83 percent of all public and private schools combined participate in the NSLP (Burghardt et al., 1993; Fox et al., 2004). About three-quarters of these schools also provide breakfast through the SBP, which is offered in approximately 78 percent of the schools that offer the NSLP (Fox et al., 2004). On an average school day, about 60 percent of children in eligible schools participate in the NSLP program and about 37 percent in the SBP (Fox et al., 2004). NSLP meals are planned to provide approximately one-third of the RDA for specific nutrients and SBP meals are planned to provide a quarter of the RDA for key nutrients. Since 1995, schools participating in the NSLP and SBP have been required by the USDA to offer meals that meet the standards established by the Dietary Guidelines for Americans. Based on national CSFII 1994–1996 data, school meal programs make an important contribution to school-aged children’s diets (Gleason and Suitor, 2001). Children who participated in the NSLP showed higher mean intakes of food calories and many micronutrients, both at lunch and over 24 hours, compared to nonparticipants. SBP participation was also associated with higher intakes of calories and several key nutrients (Gleason and Suitor, 2001). Although schools have made progress in improving meals through the NSLP and SBP, especially in decreasing fat content, they still have improvements to make to enhance the quality of the food served (Chapter 6).
Just over a decade ago, the NSLP was the primary provider of food during the school day to middle and high school students (Gleason and Suitor, 2001). Today, it represents a much smaller part of the food environment. Students, especially in middle and high schools are faced with a vast array of high-calorie (e.g., high-fat, high-sugar) food and beverage choices. These competitive foods include those sold a la carte in a cafeteria, vending machines, or school stores. Presently, there are no federal nutrition guidelines for competitive foods, unlike the USDA nutrition standards for federally funded school meals (Chapter 6). Over the last five years the availabil-
ity of competitive foods in middle schools has increased from 83 percent to 97 percent (GAO, 2005). A recent national study found that most high schools offered high-fat cookies or cakes (80 percent) or fried potatoes (62 percent) in a la carte areas, and that 95 percent had vending machines offering carbonated soft drinks, candy, or snacks. Twenty percent of middle and high schools had contracts with quick serve restaurants (Wechsler et al., 2001). In addition, the GAO (2005) recently reported that salty snacks, sweet-baked foods, carbonated soft drinks, and candy were available in at least one-third of high schools and middle schools with competitive foods, although alternative foods were commonly available in all of these schools (e.g., water, milk, juice, fruit, yogurt).
The majority of a la carte foods offered in cafeterias or vending machines are relatively high in fat and sugar and low in nutrients (French et al., 2003b). Kubik et al. (2003) examined the associations between 598 young adolescents’ dietary behaviors and school vending machines and a la carte programs. The availability of a la carte items was inversely associated with fruit and vegetable consumption and positively associated with total fat and saturated fat intake. Snack vending machines were negatively associated with fruit consumption (Kubik et al., 2003). In a longitudinal study, Cullen and Zakeri (2004) found that middle school students who had access to school snack bars consumed fewer fruits and nonstarchy vegetables, less milk, and more sweetened beverages compared to the previous school year when they were in elementary school and only had access to lunch meals served at school. These studies demonstrate that the widespread availability of high-calorie (e.g., high-fat, high-sugar) and low-nutrient foods and beverages in schools negatively impacts the diets of children and adolescents. A combination of interventions and policies are needed to reduce access to high-calorie and low-nutrient foods and beverages in schools and to promote more healthful options.
Quick Serve and Full Serve Restaurants
One of the most important food-related lifestyle changes of the past two decades is the increase of consumption of food prepared away from home. Data from the CSFII indicate that Americans consume about a third of calories from food prepared away from home, up from less than a fifth in 1977–1978 (Guthrie et al., 2002). Americans now spend 47 percent of their food dollars on meals and snacks obtained away from home (Stewart et al., 2004). Total away-from-home food expenditures amounted to $415 billion in 2002; accounting for inflation, this is a 23 percent increase since 1992 (Stewart et al., 2004). In 2002, full serve restaurants and quick serve restaurants captured the majority of the away-from-home food dollars, with 40 percent and 38 percent of total sales, respectively in 2002 (Stewart
et al., 2004). Consumer spending at full serve restaurants and quick serve restaurants is expected to increase even more over the next decade, with the larger increase at full serve restaurants (Stewart et al., 2004). Meals and snacks consumed away from home contain more calories and total fat and saturated fat than at-home foods (Guthrie et al., 2002; Lin et al., 1996; Chapter 2).
Quick serve restaurants are especially popular among families with children and adolescents because they offer convenience and relatively low cost for the meals purchased. Children and adolescents consume the largest proportion of calories away from home at quick serve restaurants (Guthrie et al., 2002). Consumption of fast food by children ages 2–17 years increased five-fold from the late-1970s to the mid-1990s, from 2 percent of total calorie intake to 10 percent (Guthrie et al., 2002). CSFII (1994–1996 and 1998) data using 24-hour diet recalls indicate that on a typical day, 30 percent of children ages 4–19 years reported consuming fast food (Bowman et al., 2004). Consumption was prevalent in both sexes, all racial/ ethnic groups, and all regions of the country; increased consumption was independently associated with male gender, older age, higher household incomes, non-Hispanic/Latino black individuals, and residing in the southern region of the United States. In a recent study, Austin et al. (2005) examined the median distance of quick serve restaurants around schools in the Chicago area. They reported that these restaurants were clustered around schools, 3 to 4 times as many quick serve restaurants were within walking distance of the school than would be expected if the restaurants were distributed evenly throughout the city.
Fast food consumption can have a negative impact on the nutritional quality of children’s and adolescents’ diets. CSFII data show that children who consumed fast food, compared with those who did not, consumed more total calories (187 additional calories) and total fat, more carbonated soft drinks, less milk, and fewer fruits and nonstarchy vegetables. In a survey of 4,746 multiethnic adolescents, French et al. (2001b) found that the frequency of quick serve restaurants use was positively associated with total calories, percentage of calories from fat, and daily servings of carbonated soft drinks and french fries, and negatively associated with daily servings of fruit, vegetables, and milk. Another study (Zoumas-Morse et al., 2001) found that while restaurant meals accounted for only 6 percent of all reported eating occasions, the calorie content of those meals was 55 percent higher than the average calorie intake of meals eaten at home.
Limited research has examined the relationships among income, race/ ethnicity, and quick serve restaurants relative to neighborhood sociodemographic characteristics. Morland et al. (2002b) examined this relationship in a four-state multiethnic study and found no consistent relationship between wealth (as measured by median home values) and
eating at quick serve restaurants. They also found no difference between the numbers of quick serve restaurants in African American and white neighborhoods. Block et al. (2004) reported contrasting results in a study using geocoding in New Orleans, Louisiana. They found that predominantly African American neighborhoods have 2.4 quick serve restaurants per square mile compared to 1.5 restaurants in predominantly white neighborhoods. However, population density was not controlled for in the analysis. More studies are needed to examine the geographic association between neighborhood quick serve restaurants density and low-income and ethnic and racial neighborhoods.
A recent study by Lewis et al. (2005) examined availability and food options at 659 restaurants in less affluent and more affluent areas in Los Angeles County to compare residents’ access to healthful meals prepared and purchased away from home. Poorer neighborhoods with a higher population of African American residents had fewer healthful options available, both in food selection and in food preparation, and the neighborhood restaurants heavily promoted the less healthful food options. The results indicate that the food environment in poorer neighborhoods makes it difficult for residents to eat healthful foods away from home.
Because Americans are eating out more frequently, eating more fruits and vegetables is a challenge. Food eaten away from home accounts for less than a half a serving of fruit, and one-and-a-quarter servings of vegetables. Fried potatoes make up approximately 35 percent of vegetables eaten away from home, compared with 10 percent of at-home vegetable consumption (Guthrie et al., 2005).
Neighborhood Characteristics and Food Retail Outlets
Neighborhood grocery stores or supermarkets are important contributors to the eating patterns and nutrient intakes of residents. Studies show that more affluent neighborhoods have greater access to supermarkets and healthful foods than low-income neighborhoods. Direct links have been observed between access to supermarkets and healthier dietary intake (Cheadle et al., 1991; Glanz and Yaroch, 2004; Laraia et al., 2004). However, nearly all of this research has been conducted with adults, not with children or adolescents. A recent study found that adult fruit and vegetable intake increased with each additional supermarket in a census tract; African Americans’ fruit and vegetable intake increased by 32 percent for each additional supermarket and whites’ intake increased by 11 percent (Morland et al., 2002a).
Supermarkets offer the greatest variety of food at the lowest cost. However, supermarkets are less prevalent in low-income neighborhoods (Horowitz et al., 2004; Morland et al., 2002b). In a multiethnic study using
census tract data across four states in different regions of the United States, Morland et al. (2002b) found that low-income neighborhoods had three times fewer supermarkets but comparable numbers of small grocers and convenience stores as middle- and upper-income neighborhoods. Zenk et al. (2005) evaluated the spatial accessibility of large chain supermarkets in relation to neighborhood racial composition and poverty in metropolitan Detroit using a geographic information system. Distance to the nearest supermarket was similar among the least impoverished neighborhoods, regardless of racial composition. However, the most impoverished neighborhoods in which African Americans lived were an average of 1.1 miles farther from the nearest supermarket than were white neighborhoods. Laraia et al. (2004) found that pregnant women living greater than 4 miles from a supermarket were more than twice as likely to have poorer quality diets compared to women living within 2 miles of a supermarket, even after controlling for individual socioeconomic status characteristics and the availability of grocery and convenience stores. In a much smaller study, child fruit and vegetable consumption was not significantly associated with availability in grocery stores (Edmonds et al., 2001).
Food retail stores in low-income neighborhoods may also offer a different mix of food. Horowitz et al. (2004) compared the selections in food stores in two adjacent New York City neighborhoods; a low-income minority neighborhood in East Harlem and an affluent, predominantly white neighborhood on the Upper East Side. Five types of products were assessed: fresh fruits, fresh green vegetables or tomatoes, high-fiber bread, low-fat milk, and diet carbonated soft drinks. Only 18 percent of East Harlem stores stocked these foods, compared with 58 percent of stores on the Upper East Side. Only 9 percent of East Harlem bodegas (small stores serving Hispanics/Latinos) carried all items versus 48 percent of Upper East Side bodegas. Collectively, these studies suggest the importance of the local neighborhood food environment for influencing diet quality.
Individual food choices depend greatly on sociocultural, marketing, and economic systems that govern food production, distribution, and consumption. The federal nutrition assistance programs and government policies can also impact the diets of participants.
Culture and Values
Cultural factors influence food behavior. Values and beliefs are core aspects of any culture and shape perceptions of food, health, and well-being. In addition to shared belief and value systems, hallmarks of culture
include language, social relationships, institutions, clothing, music, and foods. Culture embodies a socially grounded way of learning that shapes the way an individual thinks, feels, and acts (IOM, 2002). Cultural behaviors, values, and beliefs are learned in childhood, are transmitted from one generation to the next, and are often deeply held. Individuals learn to make sense of the outside world within a cultural framework and cultural processes. Within every culture, intracultural variation exists that cuts across ethnic, regional, geographic, gender, and generational domains. There is also much shared across seemingly diverse cultures. For example, media exposure (e.g., television) increases similarity across cultures. Likewise, there are examples of large quick serve restaurants and food and beverage companies that have restaurants and distribute their products in many countries around the world today and therefore may promote common food preferences among people worldwide. The growing ethnic diversity in the United States and the continuous influx of new immigrants has also contributed to exposure to new foods and preparation methods and to shifts in food preferences, as well as an expansion of the American food repertoire.
Food behaviors are learned through enculturation, which is the process by which culture is transmitted from one generation to the next. Culture influences a child’s eating behaviors both directly and indirectly. Direct influence occurs through parents, care providers, siblings, or peers. Indirect acquisition occurs through observed social norms or through marketing and the media (e.g., advertising, television, videos, movies, Internet) (Chapter 4).
Cultural values and traditions can also mediate or moderate body image and how obesity is perceived. Physical appearance and how one looks is an important issue in the lives of children and adolescents. Perception of overall appearance including body image is an important component of global self-esteem among children and adolescents (Levine and Smolak, 2002; Smolak and Levine, 2001). How much one weighs, usually an outcome of eating patterns, strongly influences physical appearance and self-image, especially for girls. Girls’ concern about physical appearance is often linked to their weight or body shape, and weight concerns and the desire to be thin appear to be developing at earlier ages. Research suggests that about 20 percent of 5-year-old girls (Davison et al., 2000), 30–45 percent of 8- to 13-year-old girls (Field et al., 1999a; Schreiber et al., 1996), and roughly 40–70 percent of adolescent girls (Levine and Smolak, 2002; Story et al., 1995) report concerns about their weight and a desire to be thinner. The widespread nature of weight and body shape dissatisfaction in adolescent girls is characterized as “normative discontent” (Levine and Smolak, 2002).
In a study of multiethnic girls in middle and high school, only a quarter (27 percent) had high body satisfaction (Kelly et al., 2005). High body satisfaction was most common among African American girls (47 percent)
and underweight girls (39 percent). Hispanic/Latina, Asian, and American Indian girls report body dissatisfaction as frequently as or more frequently than white girls (Robinson et al., 1996; Story et al., 1995).
Children and adolescents who have higher levels of body dissatisfaction and body image concerns report lower global self-worth and poorer self-esteem (Ricciardelli and McCabe, 2001; Smolak and Levine, 2001). Dissatisfaction with weight and shape and a poor body image is linked to dieting, less healthful weight control methods, depression, anxiety and eating disorders (Davison et al., 2003; Ohring et al., 2002; Stice and Whitenton, 2002). Body dissatisfaction tends to be higher in boys and girls who are heavier, although it is not restricted to those who are obese (Davison et al., 2003; Levine and Smolak, 2002; Ricciardelli and McCabe, 2001).
Gender differences in body satisfaction become apparent in late childhood. Girls have a higher prevalence of body dissatisfaction than boys and choose thinner “ideal” images for themselves (Cohane and Pope, 2001). Few studies have been conducted with boys, but recent studies report substantial numbers of adolescent boys who have weight concerns and are dissatisfied with their bodies (Labre, 2002; McCabe and Riccariardelli, 2004; Story et al., 1995). Preadolescent boys are largely satisfied with their bodies, with about one-third wanting to be thinner (McCabe and Ricciardelli, 2004). Adolescent boys tend to be equally divided between wanting to lose weight and gain weight (Cohane and Pope, 2001; McCabe and Ricciardelli, 2004). Recent reviews suggest that as the male body ideal has become increasingly muscular, body dissatisfaction has increased among adolescent males (Labre, 2002).
A major source of body dissatisfaction among girls and boys are the perceived societal pressures for them to conform to the sociocultural ideal for beauty and attractiveness (Levine and Smolak, 2002; McCabe and Ricciardelli, 2004). Sociocultural standards for males emphasize strength and muscularity and this standard appears to be consistent across a broad range of cultural groups (McCabe and Ricciardelli, 2004). Sociocultural ideals of beauty for girls emphasize thinness, although this is less pronounced for African American girls (Levine and Smolak, 2002). African American girls are more satisfied with their bodies than white, Hispanic/ Latina or American Indian girls (Kelly et al., 2005). Nichter (2000) conducted serial in-depth interviews with middle school and high school girls and found that African American girls were much more likely to be satisfied with their bodies than were the white girls. African American girls expressed that beauty was a matter of projecting attitude and moving with confidence and style rather than being thin (Nichter, 2000).
Cross-sectional surveys find that greater exposure to teen media is associated with higher weight concern (Field et al., 1999b; McCabe et al., 2002). It is hypothesized that mass media—with the pervasive emphasis on
an ideal body shape that is often unrealistically thin—is associated with internalization of the slender beauty ideal, and resulting increases in body dissatisfaction among girls (Levine and Smolak, 2002). However, superimposed on the backdrop of a “thin-ideal” for girls is the wide range of other influences on girls’ lives, including cultural factors and the subculture of her family and friends, her personal attitudes and related experiences. These factors may serve to reinforce sociocultural pressures or may act as a protective buffer and promote high body satisfaction.
The eating behaviors and physical inactivity associated with obesity have become the social norm in many communities across the United States (IOM, 2005a). Understanding the audience and the cultural and social context is the first step in designing successful health-promotion interventions (IOM, 2002). In order to be effective, nutrition and health-promotion and disease-prevention interventions need to be sensitive to salient cultural values. As individuals, families, institutions, and organizations across the United States make behavioral changes, social norms are also likely to change, so that healthful eating and regular physical activity will be the accepted and encouraged standard (IOM, 2005a).
Food Production, Processing, and Distribution Systems
The U.S. food system is a vital part of the American economy. In 2000, the food marketing system accounted for 7.7 percent of the U.S. gross domestic product and employed more than 12 percent of the U.S. labor force (Martinez, 2002). An increasing share of what consumers spend on food goes to marketing services added after the product leaves the farm. In 2000, more than 80 percent of the U.S. food dollar went toward value-added services and materials—processing, distribution, labor, packaging, and transportation. An efficient food system has resulted in an abundant and affordable food supply. Income growth has outpaced increases in food expenditures, leading to continuous reductions in the share of income spent on food (Martinez, 2002). Americans now spend less of their income on food than ever before. In 2003, expenditures for food accounted for 13.1 percent of disposable income, with 7.7 percent spent for foods at home and 5.4 percent for foods acquired away from home (U.S. Department of Labor and U.S. Bureau of Labor Statistics, 2005; Chapter 4).
The American food supply arises from a combination of domestic agricultural production and imported foodstuffs. What is actually produced and imported depends on business practices in purchasing, processing, distributing, and marketing food, and these practices are influenced by government policy and regulation. Consumer and institutional food purchases, in turn, create the markets to which businesses respond.
An analysis of the American food supply as it existed in 1996 did not match dietary recommendations according to the Food Guide Pyramid. The American food supply contained more grains, fats, and sugars than recommended, and less fruit, vegetables, dairy, and meat (Kantor, 1998). It is not clear that this imbalance between the actual food supply and healthful diets can be largely attributed to consumer demand because American agriculture is not purely market-driven. Government policies provide selective subsidies for some types of agriculture, make public lands available for activities such as cattle grazing, impose selective import restrictions and tariffs, and constrain agricultural practices for environmental and health purposes (Chapter 6). Consequently, some foods are relatively inexpensive and available in great supply, whereas others are more expensive and not widely available.
Many foods do not require intense processing and preparation. These include vegetables, fruits, nuts, meats, and dairy. These foods often have short shelf lives and require refrigeration. Branding is a marketing feature that provides a name or symbol that legally identifies a company or its product and serves as a differentiation in the marketplace (Roberts, 2004). Traditionally, these foods are not strongly associated with particular brands. More recently, branding has emerged as an important differentiation for these product categories in the marketplace. As generic foodstuffs, they are also not heavily advertised and marketed when compared to company-specific product brands.
In contrast, many manufactured foods require considerable processing before they are distributed. These foods include prepared entrees, baked goods, salty snacks, confectioneries, and carbonated soft drinks. Many of these foods are processed and manufactured to have long shelf lives and frequently do not require refrigeration. These processed foods are more likely to be strongly branded and heavily marketed and advertised. The imbalance between the food supply and the USDA food guidance system roughly approximates the differences between generic unprocessed foods and branded processed foods. The latter are much more likely to contain added sugars, sodium, fats, and oils and are also most heavily promoted through marketing communication efforts (Chapter 4). Branding does not determine the healthfulness of a food. Rather, the degree of processing, added sugar, fat, or salt, and nutrient content will determine the healthfulness of foods and beverages.
Food Marketing, Media, and Advertising
One socializing force that potentially impacts children’s eating behavior is the media. Today’s youth live in a media-saturated environment
(Rideout et al., 1999; Roberts et al., 2005). Advertising and other forms of marketing permeate nearly all media platforms to which youth are exposed (Brown and Witherspoon, 2002). Children and adolescents are currently exposed to an increasing and unprecedented amount of advertising, marketing, and commercialism through a wide range of vehicles and venues (Chapter 4). Over the past 35 years, there has been growth in a marketing research enterprise specifically focused on catering to the preferences and desires of children and youth.
Federal Food Assistance Programs
The nation’s domestic federal nutrition assistance programs provide an important source of food for many low-income children and adults. One in five Americans receive food assistance from at least one of the 15 nutrition assistance programs over the course of a year (USDA, 2005; Chapter 6). The USDA administers these programs that are designed to provide children and low-income households with access to food and a more nutritious diet, to provide nutrition education, and to assist America’s farmers by giving them an outlet for distributing foods purchased under farmer assistance programs (Levedahl and Oliveira, 1999). Even with these programs, some low-income households may still not get adequate amounts of high-quality food (Levedahl and Oliveira, 1999).
Expenditures for USDA’s 15 nutrition assistance programs totaled $46 billion in 2004. Five programs accounted for 94 percent of USDA’s total expenditures for food assistance—the Food Stamp Program (FSP); NSLP; SBP; Special Supplemental Nutrition Program for Women, Infants and Children (WIC); and CACFP. The FSP is the principal food assistance program, serving 1 in 12 Americans, or nearly 24 million low-income people per month, more than half of whom are children (USDA, 2005). The FSP provides recipients with a monthly allotment of coupons that can be redeemed for food at authorized food retail stores. Few restrictions are placed on what foods recipients can purchase. Recently, there have been targeted efforts to strengthen and reshape nutrition education in the FSP to help motivate consumers to choose healthful foods.
The WIC program provides 8 million participants with supplemental food packages each month. Participants include at-risk, low-income pregnant, breastfeeding, and postpartum women, as well as children up to age 5 years, who constitute 76 percent of all WIC participants (IOM, 2005b). Half of U.S. infants and one in four young children participate in WIC. An IOM committee recently reviewed the WIC food packages and provided comprehensive recommendations to improve its contents, such as adding more fruits and vegetables; adding more high-calcium food choices such as
yogurt, soymilk, and tofu; and expanding culturally acceptable food options (IOM, 2005b).
The Child Nutrition Programs, which include the NSLP, SBP, CACFP, and the Summer Food Programs, target children enrolled in public and nonprofit private schools, child-care institutions, and summer recreation programs. The NSLP discussed earlier is the largest of these programs, serving almost 29 million children every school day. Nearly half (49 percent) of the school lunches served are provided free to students and another 10 percent are provided at a reduced price (USDA, 2005). In recent years, there has been an increased emphasis on providing more nutritious food through these programs (Levedahl and Oliveira, 1999). Concern has centered on improving the quality of foods served in these programs, increasing the availability of fruits and vegetables, and improving the nutritional quality of commodity foods. Recently, efforts have been made to pilot programs to promote fresh fruits and vegetables in schools. The 2002 Farm Bill provided funds for the Fruit and Vegetable Pilot Program (FVPP) in 25 schools in four states and one Indian reservation (ERS, 2002). The recent Child Nutrition and WIC Reauthorization Act expanded the program to four more states and two more Indian reservations (Committee on Education and the Workforce, 2004).
Although the USDA’s nutrition assistance programs vary greatly in size, target populations, and delivery mechanisms, they all provide children of low-income households with food, the means to purchase food, and nutrition education. Although the food assistance programs have been shown to increase the quantity of food consumed by participants, the effect of these programs on improving the quality of their diets has been more difficult to ascertain (Levedahl and Oliveira, 1999). Although a number of studies have attempted to quantify the effects of the nutrition assistance programs, there has been no comprehensive assessment of the effects of the programs on the diet and health outcomes of participants. A recent USDA-funded study reviewed research on the impact of the USDA’s nutrition assistance programs on participants’ health and diet outcomes. The main conclusion is that findings must be interpreted with caution due to the limitations of the studies (Fox et al., 2004). For targeted programs such as WIC, the NSLP, and SBP, nutrient intake is generally increased. The FSP increases household food intake, although whether nutritional quality is higher is unclear (Fox et al., 2004). There is a need for a well-designed comprehensive study on how nutrition and health status are impacted by participation in nutrition assistance programs.
Nutrition assistance programs serve a large proportion of low-income children who need these programs to meet their daily calorie and nutritional needs. These children should have access to nutrient-rich foods that are ethnically and culturally appropriate. The USDA could explore innova-
tive pilot programs to increase access to healthful foods or provide incentives for the purchase of these items. Examples include further expanding the FVPP to more schools; supporting farm-to-school programs, school gardens, and WIC gardens, ensuring that food stamp recipients have access to supermarkets, farmers’ markets, and other venues to provide fresh, high-quality, and affordable produce, and other healthful foods, fruit and vegetable vouchers, or bonus coupons for food stamp users (IOM, 2005a; Chapter 6).
Government Regulations and Policies
Government policies and regulations related to food and agriculture can directly and indirectly affect the supply or prices of food, the nutritional composition of foods, food safety, the information consumers receive about food, and consumer confidence in the food supply, all of which can influence consumer food choices (Ralston, 1999). As discussed in more depth in Chapter 6, the effects of policies and regulations, such as subsidies and taxation, on food choices depends on how the policy affects the cost of producing commodities, how those costs relate to final retail prices, how responsive consumers are to price changes, and how the policy directly influences consumer preference for the product (Ralston, 1999).
A highly productive and efficient agriculture production system contributes to an ample supply of food in the United States. However, there has been little examination of how agricultural and economic public policies and the resulting food and agricultural environment affect food choice or obesity (Tillotson, 2004), including how the types and quantities of foods available through the federal food and nutrition assistance programs influence healthy diets for children and youth.
The committee’s review of the elements shaping the food and beverage consumption of children and adolescents underscores the importance of using an ecological perspective to understand the interactions among factors that influence food preferences and eating behaviors. Multiple influences—individual and developmental factors, family and social elements, institutions, communities, and macrosystems—interact to shape the food and beverage consumption patterns of children and youth. This ecological perspective can be used to develop more effective strategies and programs to improve dietary behaviors.
Nutrition knowledge of children and youth by itself does not necessarily motivate their food choices and dietary behaviors. Food preferences develop as early as ages 2–3 years and are shaped by a child’s early experi-
ences, positive or negative conditioning, exposure to foods, and a biological predisposition to prefer sweet, high-fat, and salty foods. Thus, the challenge of helping young people adopt healthful eating behaviors will require multifaceted and coordinated efforts aimed at the individual and family, the physical environment such as schools and neighborhoods, the macrosystem such as the food marketing system, and government policies and regulations. These efforts need to focus on changing individual behaviors, the social environment, and social norms around eating behaviors. Individual change is more likely to be facilitated and sustained in an environment that supports healthful food choices. Special attention needs to be focused on ensuring that low-income and ethnic minority children and youth have access to healthful and nutritious foods and beverages.
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