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OCR for page 79
4
Weight-Loss and Maintenance
Strategies
The most important component of an effective weight-management pro-
gram must be the prevention of unwanted weight gain Dom excess body fat. The
military is in a unique position to address prevention from the first day of an
individual's military career. Because the military population is selected from a
pool of individuals who meet specific criteria for body mass index (BMI) and
percent body fat, the primary goal should be to foster an environment that pro-
motes maintenance of a healthy body weight and body composition throughout
an individual's military career. There is significant evidence that losing excess
body fat is difficult for most individuals and the risk of regaining lost weight is
high. From the first day of initial entry training, an understanding of the funda-
mental causes of excess weight gain must be communicated to each individual,
along with a strategy for maintaining a healthy body weight as a way of life.
INTRODUCTION
The principle of weight gain is simple: energy intake exceeds energy
expenditure. However, as discussed in Chapter 3, overweight and obesity are
clearly the result of a complex set of interactions among genetic, behavioral, and
environmental factors. While hundreds, if not thousands, of weight-loss strate-
gies, diets, potions, and devices have been offered to the overweight public, the
multi-factorial etiology of overweight challenges practitioners, researchers, and
the overweight themselves to identify permanent, effective strategies for weight
loss and maintenance. The percentage of individuals who lose weight and
successfully maintain the loss has been estimated to be as small as 1 to 3 percent
(Andersen et al., 1988; Wadden et al., 19891.
Evidence shows that genetics plays a role in the etiology of overweight and
obesity. However, genetics cannot account for the increase in overweight
observed in the U.S. population over the past two decades. Rather, the behav-
ioral and environmental factors that conspire to induce individuals to engage in
79
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80
TABLE 4-1 Benefits of Physical Activity
WEIGHT MANAGEMENT
Benefit
Improved maintenance of lost weight
Reference
Pavlouetal., 1989a, 1989b;Phinney, 1992;
Skender et al., 1996; Wadden, 1993;
Wing, 1992; Wing arid Greeno, 1994
Calles-Esearldon arid Horton, 1992; Wad-
den, 1993
Calles-Eseandon and Horton, 1992
Preservation of lean body mass
Improved cardiovascular, respiratory,
and museuloskeletal fitness
Improved psychological profile arid self-
esteem
Improved mood
Improved plasma blood glucose levels,
blood pressure, and blood lipid and
lipoprotein values
Reduced risk for morbidity and mortality
ACSM, 2000
Wadden, 1993
Calles-Esear~don and Horton, 1992; Pate et
al., 1995; Pavlou et al., 1989a, 1989b
Blair, 1993; Dyer, 1994; Pate et al., 1995
too little physical activity and eat too much relative to their energy expenditure
must take most of the blame. It is these factors that are the target of weight-
management strategies. This chapter reviews the efficacy and safety of strategies
for weight loss, as well as the combinations of strategies that appear to be
associated with successful loss. In addition, the elements of successful weight
maintenance also will be reviewed since the difficulty in maintaining weight
loss may contribute to the overweight problem. A brief discussion of public
policy measures that may help prevent overweight and assist those who are
trying to lose weight or maintain weight loss is also included.
PHYSICAL ACTIVITY
Increased physical activity is an essential component of a comprehensive
weight-reduction strategy for overweight adults who are otherwise healthy. One
of the best predictors of success in the long-term management of overweight and
obesity is the ability to develop and sustain an exercise program (Jakicic et al.,
1995, 1999; Klem et al., 1997; McGuire et al., 1998, 1999; Schoeller et al.,
1997~. The availability of exercise facilities at military bases can reinforce
exercise and fitness programs that are necessary to meet the services' physical
readiness needs generally, and for weight management specifically. For a given
individual, the intensity, duration, frequency, and type of physical activity will
depend on existing medical conditions, degree of previous activity, physical
limitations, and individual preferences. Referral for additional professional
evaluation may be appropriate, especially for individuals with more than one of
the above extenuating factors. The benefits of physical activity (see Table 4-1)
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WEIGHT-LOSS AND MAINTENANCE STRA TEGIES
81
are significant and occur even in the absence of weight loss (Blair, 1993;
Kesaniemi et al., 2001~. It has been shown that one of the benefits, an increase
in high-density lipoproteins, can be achieved with a threshold level of aerobic
exercise of 10 to 1 1 hours per month.
For previously sedentary individuals, a slow progression in physical activity
has been recommended so that 30 minutes of exercise daily is achieved after
several weeks of gradual build-up. This may also apply to some military
personnel, especially new recruits or reservists recalled to active duty who may
be entering service Mom previously very sedentary lifestyles. The activity goal
has been expressed as an increase in energy expenditure of 1,000 kcal/wk
(Jakicic et al., 1999; Pate et al., 1995), although this quantity may be insufficient
to prevent weight regain. For that purpose, a weekly goal of 2,000 to 3,000 kcal
of added activity may be necessary (Klem et al., 1997; Schoeller et al., 1997~.
Thus, mental preparation for the amount of activity necessary to maintain weight
loss must begin while losing weight (Brownell, 1999~.
For many individuals, changing activity levels is perceived as more un-
pleasant than changing dietary habits. Breaking up a 30-m~nute daily exercise
"prescription" into 1 O-minute bouts has been shown to increase compliance over
that of longer bouts (Jakicic et al., 1995, Pate et al., 1995~. However, over an 18-
month period, individuals who performed short bouts of physical activity did not
experience improvements in long-term weight loss, cardiorespiratory fitness, or
physical activity participation in comparison with those who performed longer
bouts of exercise. Some evidence suggests that home exercise equipment (e.g., a
treadmill) increases the likelihood of regular exercise and is associated with
greater long-term weight loss (Jakicic et al., 1999~. In addition, individual
preferences are paramount considerations in choices of activity.
When strength training or resistance exercise is combined with aerobic
activity, long-term results may be better than those with aerobics alone (Poirier
and Despres, 2001; Sothern et al., 1999~. Because strength training tends to
build muscle, loss of lean body mass may be minimized and the relative loss of
body fat may be increased. An added benefit is the attenuation of the decrease in
resting metabolic rate associated with weight loss, possibly as a consequence of
preserving or enhancing lean body mass.
As valuable as exercise is, the existing research literature on overweight
individuals indicates that exercise programs alone do not produce significant
weight loss in the populations studied. It should be emphasized, however, that a
large number of such studies have been conducted with middle-aged Caucasian
women leading sedentary lifestyles. The failure of exercise alone to produce
significant weight loss may be because the neurochemical mechanisms that
regulate eating behavior cause individuals to compensate for the calories
expended in exercise by increasing food (calorie) intake. While exercise pro-
grams can result in an average weight loss of 2 to 3 kg in the short-term (Blair,
1993; Pavlou et al., 1989a; Skender et al., 1996, Wadden and Sarwer, 1999),
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82
WEIGHT AL4NAGEMENT
outcome improves significantly when physical activity is combined with dietary
intervention. For example, when physical activity was combined with a reduced-
calorie diet and lifestyle change, a weight loss of 7.2 kg was achieved after 6
months to 3 years of follow-up (Blair, 1993~. Physical activity plus diet
produces better results than either diet or physical activity alone (Blair, 1993;
Dyer, 1994; Pavlou et al., 1989a, 1989b; Perri et al., 1993~. In addition, weight
regain is significantly less likely when physical activity is combined with any
other weight-reduction regimen (Blair, 1993; Klem et al., 1997~. Continued
follow-up after weight loss is associated with improved outcome if the activity
plan is monitored and modified as part of this follow-up (Kayman et al., 1990~.
While studies have shown that military recruits were able to lose significant
amounts of weight during initial entry training through exercise alone, the
restricted time available to consume meals during Gaining probably contributed
to this weight loss (Lee et al., 1994~.
BEHAVIOR AND LIFESTYLE MODIFICATION
The use of behavior and lifestyle modification in weight management is
based on a body of evidence that people become or remain overweight as the
result of modifiable habits or behaviors (see Chapter 3), and that by changing
those behaviors, weight can be lost and the loss can be maintained. The primary
goals of behavioral strategies for weight control are to increase physical activity
and to reduce caloric intake by altering eating habits (Brownell and Kramer,
1994; Wilson, 1995~. A subcategory of behavior modification, environmental
management, is discussed in the next section. Behavioral treatment, which was
introduced in the 1960s, may be provided to a single individual or to groups of
clients. Typically, individuals participate in 12 to 20 weekly sessions that last
*om 1 to 2 hours each (Brownell and Kramer, 1994), with a goal of weight loss
in the range of 1 to 2 lb/wk (Brownell and Kramer, 1994~. In the past, behavioral
approaches were applied as stand-alone treatments to simply modify eating
habits and reduce caloric intake. However, more recently, these treatments have
been used in combination with low-calorie diets, medical nutrition therapy,
nutrition education, exercise programs, monitoring, pharmacological agents, and
social support to promote weight loss, and as a component of maintenance
programs.
Self-Monitoring and Feedback
Self-monitoring of dietary intake and physical activity, which enables the
individual to develop a sense of accountability, is one of the cornerstones of
behavioral treatment. Patients are asked to keep a daily food diary in which they
record what and how much they have eaten, when and where the food was
consumed, and the context in which the food was consumed (e.g., what else they
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WEIGHT-LOSS AND MAINTENANCE STRA TEGIES
83
were doing at the time, what they were feeling, and who else was there).
Additionally, patients may be asked to keep a record of their daily physical
activities. Self-monitoring of food intake is open associated with a relatively
immediate reduction in food intake and consequent weight loss (Blundell, 2000;
Goris et al., 2000~. This reduction in food intake is believed to result from
increased awareness of food intake and/or concern about what the dietitian or
nutrition therapist will think about the patient's eating behavior. The information
obtained from the food diaries also is used to identify personal and environ-
mental factors that contribute to overeating and to select and implement
appropriate weight-loss strategies for the individual (Wilson, 1995~. The same
may be true of physical activity monitoring, although little research has been
conducted in this area. Self-monitoring also provides a way for therapists and
patients to evaluate which techniques are working and how changes in eating
behavior or activity are contributing to weight loss. Recent work has suggested
that regular self-monitoring of body weight is a useful adjunct to behavior
modification programs (Jeffery and French, 1999~.
Other Behavioral Techniques
Some additional techniques included in behavioral treatment programs
include eating only regularly scheduled meals; doing nothing else while eating;
consuming meals only in one place (usually the dining room) and leaving the
table after eating; shopping only from a list; and shopping on a full stomach
(Brownell and Kramer, 1994~.
Reinforcement techniques are also an integral part of the behavioral treat-
ment of overweight and obesity. For example, subjects may select a positively
reinforcing event, such as participating in a particularly enjoyable activity or
purchasing a special item when a goal is met (Brownell and Kramer, 1994~.
Another important component of behavioral treatment programs may be
cognitive restructuring of erroneous or dysfunctional beliefs about weight
regulation (Wing, 19981. Techniques developed by cognitive behavior therapists
can be used to help the individual identify specific triggers for overeating, deal
with negative attitudes towards obesity in society, and realize that a minor
dietary infraction does not mean failure. Nutrition education and social support,
discussed later in this chapter, are also components of behavioral programs.
Behavioral treatments of obesity are frequently successful in the short-term.
However, the long-term effectiveness of these treatments is more controversial,
with data suggesting that many individuals return to their initial body weight
within 3 to 5 years after treatment has ended (Brownell and Kramer, 1994; Klem
et al., 19971. Techniques for improving the long-term benefits of behavioral
treatments include: (l) developing criteria to match patients to treatments, (2)
increasing initial weight loss, (3) increasing the length of treatment, (4) empha-
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WEIGHT AL4NAGEMENT
sizing the role of exercise, and (5) combining behavioral programs with other
treatments such as pharmacotherapy, surgery, or stringent diets (Brownell and
Kramer, 1994~.
Recent studies of individuals who have achieved success at long-term
weight loss may offer other insights into ways to improve behavioral treatment
strategies. In their analysis of data Tom the National Weight Control Registry,
Klem and coworkers (1997) found that weight loss achieved through exercise,
sensible dieting, reduced fat consumption, and individual behavior changes
could be maintained for long periods of time. However, this population was self-
selected so it does not represent the experience of the average person in a civil-
ian population. Because they have achieved and maintained a significant amount
of weight loss (at least 30 lb for 2 or more years), there is reason to believe that
the population enrolled in the Registry may be especially disciplined. As such,
the experience of people in the Registry may provide insight into the military
population, although evidence to assert this win authority is lacking. In any
case, the majority of participants in the Registry report they have made signifi-
cant permanent changes in their behavior, including portion control, low-fat
food selection, 60 or more minutes of daily exercise, self-monitoring, and well-
honed problem-solving skills.
Eating Environments
A significant part of weight loss and management may involve restructuring
the environment that promotes overeating and underactivity. The environment
includes the home, the workplace, and the community (e.g., places of worship,
eating places, stores, movie theaters). Environmental factors include the avail-
ability of foods such as fruits, vegetables, nonfat dairy products, and other foods:
of low energy density and high nutritional value. Environmental restructuring-
empha-sizes frequenting dining facilities that produce appealing foods of lower
energy density and providing ample time for eating a wholesome meal rather
than grabbing a candy bar or bag of chips and a soda from a vending machine.
Busy lifestyles and hectic work schedules create eating habits that may
contribute to a less than desirable eating environment, but simple changes can
help to counter-act these habits.
Commanders of military bases should examine their facilities to identify
and eliminate conditions that encourage one or more of the eating habits that
promote overweight. Some nonmilitary employers have increased healthy eating
options at worksite dining facilities and vending machines. Although multiple
publications suggest that worksite weight-loss programs are not very effective in
reducing body weight (Cohen et al., 1987; Forster et al., 1988; Frankle et al.,
l 986; Kneip et al., 1985; Loper and Barrows, 1985), this may not be the case for
the military due to the greater controls the military has over its "employees"
than do nonmilitary employers.
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NEIGH T-LOSS AND MAINTENANCE STRA TEGIES
85
Eating habits that may promote overweight:
1. Eating few or no meals at home
2. Opting for high-fat, calorie-dense foods
3. Opting for high-fat snack foods from strategically placed vending ma-
chines or snack shops combined with allowing insufficient time to pre-
pare affordable, healthier alternatives.
4. Consuming meals at sit-down restaurants that feature excessive portion
sizes or"all-you-can-eat" buffets
Simple changes that can modify the eating environment:
1. Prepare meals at home and can y bag lunches
Learn to estimate or measure portion sizes in restaurants
Learn to recognize fat content of menu items and dishes on buffet tables
4. Eliminate smoking and reduce alcohol consumption
Substitute low-calorie for high-calorie foods
6. Modify the route to work to avoid a favorite food shop
Physical Activity Environment
Major obstacles to exercise, even in highly motivated people, include the
time it takes to complete the task and the inaccessibility of facilities or safe
places to exercise. Environmental interventions emphasize the many ways that
physical activity can be fit into a busy lifestyle and seek to make use of what-
ever opportunities are available (HHS, 1996~. Environmental changes may be
needed to encourage female participation in exercise programs, such as accom-
modation of the need for more after-exercise "repair time" by women and work-
site facilities that are more "user friendly," such as measured indoor walking
routes and lunchtime low-level aerobics classes (Wasserman et al., 20001. The
availability of safe sidewalks and parks and alternative methods of transporta-
tion to work, such as walking or bicycling, also enhance the physical activity
environment. Establishing "car-free" zones is an example of an environmental
change that could promote increased physical activity.
Nutrition Education
Management of overweight and obesity requires the active participation of
the individual. Nutrition professionals can provide individuals with a base of
information that allows them to make knowledgeable food choices.
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86
WEIGHT MANAGEMENT
Nutrition education is distinct from nutrition counseling, although the con-
tents overlap considerably. Nutrition counseling and dietary management tend to
focus more directly on the motivational, emotional, and psychological issues
. . . . , . . . . ~ · ~ . 1 ~ ~ ~ be. ~ _ _ ~_~ ~~~ 1 ~
OaaQ~l~LG~ WlLll ally ~Ull~llL ~~ w~ ~~—~~AA~ A~— ~~ ~~ .,_ . In
addresses the how of behavioral changes in the dietary arena. Nutrition
education on the other hand, provides basic information about the scientific
foundation of nutrition that enables people to make infonned decisions about
food, cooking methods, eating out, and estimating portion sizes. Nutrition
education programs also may provide information on the role of nutrition in
health promotion and disease prevention, sports nutrition, and nutrition for
pregnant and lactating women. Effective nutrition education imparts nutrition
knowledge and its use in healthy living. For example, it explains the concept of
energy balance in weight management in an accessible, practical way that has
meaning to the individual's lifestyle, including that in the military setting.
Written materials prepared by various government agencies or by nonprofit
health organizations can be used effectively to provide nutrition education.
However, written materials are most effective when used to reinforce informal
classroom or counseling sessions and to provide specific information, such as a
table of the calorie content of foods. The format of education programs varies
considerably, and can include formal classes, informal group meetings, or
teleconferencing. A common background among group members is helpful (but
seldom possible).
~^A~;~+~ ,;+h The ^..~^t tack Of ~~rPiabt lr~cc ~nr1 Vomit m~nnu~ment
Educational formats that provide practical and relevant nutrition informa-
tion for program participants are the most successful. For example, some mili-
tary weight-management programs include field trips to post exchanges, restau-
rants (fast-food and others), movies, and other places where food is purchased or
consumed (Vorachek, 1999~.
The involvement of spouses and other family members in an education pro-
gram increases the likelihood that other members of the household will make
permanent changes, which in turn enhances the likelihood that the program par-
ticipants will continue to lose weight or maintain weight loss (Hart et al., 1990;
Hertzler and Schulman, 1983; Sperry, 1985~. Particular attention must tee di-
rected to involvement of those in the household who are most likely to shop for
and prepare food. Unless the program participant lives alone, nutrition manage-
ment is rarely effective without the involvement of family members.
DIET
Weight-management programs may be divided into two phases: weight loss
and weight maintenance. While exercise may be the most important element of a
weight-maintenance program, it is clear that dietary restriction is the critical
component of a weight-loss program that influences the rate of weight loss.
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES
87
Activity accounts for only about 15 to 30 percent of daily energy expenditure,
but food intake accounts for 100 percent of energy intake. Thus, the energy bal-
ance equation may be affected most significantly by reducing energy intake. The
number of diets that have been proposed is almost innumerable, but whatever
the. name, all diets consist of reductions of some proportions of protein, carbo-
hydrate (CHO) and fat. The following sections examine a number of arrange-
ments of the proportions of these three energy-containing macronutrients.
Nutritionally Balanced, Hypocaloric Diets
A nutritionally balanced, hypocaloric diet has been the recommendation of
most dietitians who are counseling patients who wish to lose weight. This type
of diet is composed of the types of foods a patient usually eats, but in lower
quantities. There are a number of reasons such diets are appealing, but the main
reason is that the recommendation is simple—individuals need only to follow
the U.S. Department of Agriculture's Food Guide Pyramid. The Pyramid
recommends that individuals eat a variety of foods, with the majority being
grain products (e.g., bread, pasta, cereal, rice), eat at least five servings per day
of fruits and vegetables; eat only moderate amounts of dairy and meat products;
and limit the consumption of foods that are high in fat or sugar or contain few
nutrients. In using the Pyramid, however, it is important to emphasize the
portion sizes used to establish the recommended number of servings. For
example, a majority of consumers do not realize that a portion of bread is a
single slice or that a portion of meat is only 3 oz.
A diet based on the Pyramid is easily adapted from the foods served in
group settings, including military bases, since all that is required is to eat smaller
portions. Even with smaller portions, it is not difficult to obtain adequate
quantities of the other essential nutrients. Many of the studies published in the
medical literature are based on a balanced hypocaloric diet with a reduction of
energy intake by 500 to 1,000 kcal Mom the patient's usual caloric intake. The
U.S. Food and Drug Administration (FDA) recommends such diets as the
"standard treatment" for clinical trials of new weight-loss drugs, to be used by
both the active agent group and the placebo group (FDA, 19961.
Meal Replacement
Meal replacement programs are commercially available to consumers for a
reasonably low cost. The meal replacement industry suggests replacing one or
two of the three daily meals with their products, while the third meal should be
sensibly balanced. In addition, two snacks consisting of fruits, vegetables, or
diet snack bars are recommended each day. Using this plan, individuals con-
sume approximately 1,200 to 1,500 kcal/day.
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WEIGHT MANAGEMENT
A number of studies have evaluated long-term weight maintenance using
meal replacement, either self-managed (Flechtner-Mors et al., 2000; Heber et
al., 1994; Rothacker, 2000), with active dietary counseling, or with behavior
modification programs (Ashley et al., 2001; Ditschuneit and Flechtner-Mors,
2001; Ditschuneit et al., 1999) compared with traditional calorie-restricted diet
plans. The largest amount of weight loss occurred early in the studies (about the
first 3 months of the plan) (Ditschuneit et al., 1999; Heber et al., 1994~. One
study found that women lost more weight between the third and sixth months of
the plan, but men lost most of their weight by the third month (Heber et al.,
1994~. All of the studies resulted in maintenance of significant weight loss after
2 to 5 years of follow-up. Hill's (2000) review of Rothacker (2000) pointed out
that the group receiving meal replacements maintained a small, yet significant,
weight loss over the 5-year program, whereas the control group gained a signifi-
cant amount of weight. Active intervention, which included dietary counseling
and behavior modification, was more effective in weight maintenance when
meal replacements were part of the diet (Ashley et al., 2001~. Meal replacements
were also found to improve food patterns, including nutrient distribution, intake
of micronutrients, and maintenance of fruit and vegetable intake.
Long-term maintenance of weight loss with meal replacements improves
biomarkers of disease risk, including improvements in levels of blood glucose
(Ditschuneit and Fletchner-Mors, 2001), insulin, and triacylglycerol; improved
systolic blood pressure (Ditschuneit and Fletchner-Mors, 2001; Ditschuneit et
al., 19994; and reductions in plasma cholesterol (Heber et al., 1994~.
Winick and coworkers (2002) evaluated employees in high-stress jobs (e.g.,
police, firefighters, and hospital and aviation personnel) who participated in
worksite weight-reduction and maintenance programs that used meal replace-
ments. The meal replacements were found to be effective in reducing weight and
maintaining weight loss at a 1-year follow-up. In contrast, Bendixen and co-
workers (2002) reported from Denmark that meal replacements were associated
with negative outcomes on weight loss and weight maintenance. However, this
was not an intervention study; participants were followed for 6 years by phone
interview and data were self-reported.
Unbalanced, Hypocaloric Diets
Unbalanced, hypocaloric diets restrict one or more of the calorie-containing
macronutrients (protein, fat, and CHO). The rationale given for these diets by
their advocates is that the restriction of one particular macronutrient facilitates
weight loss, while restriction of the others does not. Many of these diets are
published in books aimed at the lay public and are often not written by health
professionals and often are not based on sound scientific nutrition principles. For
some of the dietary regimens of this type, there are few or no research
publications and virtually none have been studied long term. Therefore, few
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES
89
conclusions can be drawn about the safety, and even about the efficacy, of such
diets. The major types of unbalanced, hypocaloric diets are discussed below.
High-Protein, Low-Carbohydrate Diets
There has been considerable debate on the optimal ratio of macronutrient
intake for adults. This research usually compares the amount of fat and CHO;
however, there has been increasing interest in the role of protein in the diet (Hu
et al., 1999; Wolfe and Giovannetti, 1991~. Studies have looked for the effects
of a higher protein diet (CHO/prote~n ratio ~1.0) compared with a higher CHO
diet (CHO/protein ratio ~3.0~. Although the high-protein diet does not produce
significantly different weight loss compared with the high-CHO diet (Layman et
al., 2003a, 2003b; Piatti et al., 1994), the high-protein diet has been reported to
stimulate greater improvements in body composition by sparing lean body mass
(Layman et al., 2003a; Piatti et al., 1994~.
High-protein, low-CHO diets were introduced to the American public
during the 1970s and 1980s by Stillman and Baker (1978) and by Atkins
(Atkins, 1988; Atkins and Linde, 1978), and more recently, by Sears and
Lawren (1998~. Some of these diets are high in fat (> 35 percent of kcal), while
others have moderate levels of fat (25-35 percent of kcal). While most of these
diets have been promoted by nonscientists who have done little or no serious
scientific research, some of the regimens have been subjected to rigorous studies
(Skov et al., 1999a, l999b). There remains, however, a lack of randomized
clinical trials of 2 or more years' duration, which are needed to evaluate the
potent beneficial effect of weight loss (accomplished using virtually any dietary
regimen, no matter how unbalanced) on blood lipids. In addition, longer studies
are needed to separate the beneficial effects of weight loss from the long-term
effects of consuming an unbalanced diet.
Authors of books aimed at the lay public have proposed advantages of high
protein diets, including that eating a high-protein, low-CHO diet produces a
"near-euphoric" state of maximal physical and mental performance (Sears and
Lawren, 1998~. These claims are unsupported by scientific data.
Although these diets are prescribed to be eaten ad libitum, total daily energy
intake tends to be reduced as a result of the monotony of the food choices, other
prescripts of the diet, and an increased satiety effect of protein. In addition, the
restriction of CHO intake leads to the loss of glycogen and marked diuresis
(Coulston and Rock, 1994; Miller and Lindeman, 1997; Pi-Sunyer, 19884. Thus,
the relatively rapid initial weight loss that occurs on these diets predominantly
reflects the loss of body water rather than stored fat. This can be a significant
concern for military personnel, where even mild dehydration can have detri-
mental effects on physical and cognitive performance. For example, small
changes in hydration status can affect a military pilot's ability to sense changes
. .... .
In equlllorlum.
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WEIGHT MANAGEMENT
available data suggest that combination therapy is somewhat more effective than
therapy with single agents. Combinations such as phentermine and fenfluramine
or ephedrine and caffeine produce weight losses of about 15 percent or more of
initial body weight compared with about 10 percent or less with single drug use.
However, due to reported side-effects of cardiac valve lesions and pulmonary
hypertension, fenfluramine and dextenfluramine are no longer available.
Results of tests using combinations of phentermine with selective serotonin
reuptake inhibitors (mainly fluoxetine or sertraline) have been reported in ab-
stracts or preliminary reports (Dhuran&ar and Atkinson, 1996; Griffen and An-
chors, 1998~. These combinations produced weight losses somewhat less than
that of the combination treatment of ephedrine-caffeine, but greater than that of
treatment with single agents (Dhurandhar and Atkinson, 1996~.
Safer. Anchors (1997) used the combination of phentermine and fluoxetine
in a large series of patients and suggested that this combination is safe and effec-
tive. Griffen and Anchors (1998) reported that the combination of phentermine-
fluoxetine was not associated with the cardiac valve lesions that were reported
for fenfluramine and dexfenfluramine.
Alternative Medicines, Herbs, and Diet Supplements
In 1994, Congress passed the Dietary Supplement Health and Education
Act, which exempted dietary supplements (including those promoted for weight
loss) from the requirement to demonstrate safety and efficacy. As a result, the
variety of over-the-counter preparations touted to promote weight loss has ex-
ploded. Dietary supplements include compounds such as herbal preparations
(often of unknown composition), chemicals (e.g., hydroxycitrate, chromium),
vitamin preparations, and protein powder preparations. With the exception of
herbal preparations of ephedrine and caffeine, none of these compounds have
produced more than a minimal weight loss and most are ineffective or have been
insufficiently studied to determine their efficacy. Furthermore, while little is
known about the safety of many of these compounds, there are a growing num-
ber of adverse event reports for several of them. Table 4-4 summarizes the cur-
rent safety and efficacy profile of a number of alternative compounds promoted
for the purpose of weight loss.
The combination of ephedrine and caffeine to treat obesity has been re-
ported to produce weight losses of 15 percent or more of initial body weight
(Daly et al., 1993; Toubro et al., 1993~. Both drugs are the active ingredients in a
number of herbal weight-loss preparations. Weight loss is maximal at about 4 to
6 months on this combination, but body-fat levels may continue to decrease
through 9 to 12 months, with increases in lean body mass (Toubro et al., 1993~.
This observation suggests that the combination may be a beta-3 adrenergic ago-
nist (Liu et al., 1995; Toubro et al., 19939.
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WEIGHT-LOSS AND MAINTENANCE STRA TEGIES
103
Reports of cardiovascular and cerebrovascular events following use of
ephedrine and caffeine to treat obesity have reached sufficient frequency that
FDA and the Federal Trade Commission have begun to investigate the safety of
this combination and have issued warnings to consumers. In addition, FDA has
proposed new regulations for the labeling of products containing ephedrine,
which would require warning statements for potential adverse health effects.
Use of ephedrine alone or in combination with caffeine has been associated with
a wide range of cardiovascular, cerebrovascular, neurological, psychological,
gastrointestinal, and other symptoms in adverse events reports (Hailer and Be-
nowitz, 2000; Shekelle et al., 2003~. Some prospective studies do not support the
concept that there are major adverse events with ephedrine and caffeine (Boozer
et al., 2001, 2002; Greenway, 2001; Kalman et al., 2002), but these studies were
conducted using healthy individuals selected using careful exclusion criteria.
FUTURE DRUGS FOR THE TREATMENT OF OBESITY
Body weight, body fat, energy metabolism, and fat oxidation are regulated
by numerous hormones, peptides, neurotransmitters, and other substances in the
body. Drug companies are devoting a large amount of resources to find new
agents to treat obesity. Potential candidates include cholecystokinin, cortioco-
tropin-releasing hormone, glucagon-like peptide 1, growth hormone and other
growth factors, enterostatin, neurotensin, vasopressin, anorectin, ciliary neuro-
trophic factor, and bombesin, all of which potentially either inhibit food intake
or reduce body weight in humans or animals (Bray, 1992b, 1998; Ettinger et al.,
2003; Okada et al., 1991; Rudman et al., 1990; Smith and Gibbs, 1984~.
Neuropeptide Y and galanin are central nervous system neurotransmitters that
stimulate food intake (Bray, 1998; Leibowitz, 1995), so antagonists to these
substances might be expected to reduce food intake. Beta-3 adrenergic receptor
agonists reduce body fat and increase lean body mass in animals (Stock, 1996;
Yen, 1995), but human analogs have not been identified that are effective and
safe in humans. Several types of uncoupling proteins have been identified as
being involved with the regulation of energy metabolism and body fat (Bao et
al., 1998; Bouchard et al., 1998; Chagnon et al., 2000; Perusse et al., 1999), but
no agents based on these proteins have yet been produced to treat obesity.
As discussed in Chapter 3, seven single gene defects have been reported to
produce obesity in humans (Perusse et al., 1999~. The leptin gene is defective in
ob/ob mice, and leptin administration has been shown to be highly effective in
reducing body weight in these mice (Campfield et al., 1995; Halaas et al., 1995;
Pelleymounter et al., 19953. A very small number of humans with this gene de-
fect have been identified, and at least one responded to leptin (Clement et al.,
1998; Perusse et al., 19991. Leptin levels are high in most obese individuals
(Considine et al., 1996; Phillips, 1998), and preliminary trials of administration
of leptin to these individuals show modest effects. Defects in the genes for
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104
WEIGHT MANAGEMENT
TABLE 4-4 Alternative Medicines, Herbs, and Supplements Used for Weight
Loss
Name/Compound Description
Bladderwrack
Chitosan
Chromium
CLA
DHEA
Ephedrine fat-burning stack
Garcinia cambogia
Germander
HMB
Olestra (Lawson et al., 1997)
Plantago
Pyruvate
Sunflower
St. John's Wort
SOURCE: Allison et al. (2001~.
Fucus vesiculosus
Polymer of glucosamine derived from chitin
Cr—an essential element
Conjugated linoleic acid
Dehydroepiar~drosterone
Ephedrine with caffeine and aspirin, ma huang
with guarana and willow bark
Contains hydroxycitrate (HCA)
Teucrium chamaedrys
,B-Hydroxy-p-methylbutryrate
Mixture of hexa-, hepta-, and octa-esters of
sucrose formed from long-chain fatty acids
isolated from edible oils
Plantain leaf or psyllium seed
A 3-carbon compound
Heliallthus annuus
Hypericum perforatum
protein convertase subtilisin/kexin type 1, PPAR-gamma, and pro-opiomelano-
cortin and in the genes for the receptors for leptin, thyroid hormone, and
melanocortin-4R (Bouchard et al., 1998; Chagnon et al., 2000; Perusse et al.,
1999) have been identified in humans. It may be possible in the future to
develop gene therapy or products that correct these defects in order to treat
obesity.
Summary
Although obesity drugs have been available for more than 50 years, the
concept of long-term treatment of obesity with drugs has been seriously
advanced only in the last 10 years. The evidence that obesity, as opposed to
overweight, is a pathophysiological process of multiple etiologies and not
simply a problem of self-discipline is gradually being recognized~besity is
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES
105
Safety Efficacy for Weight/Fat Loss
No, increases risk of hyperthyroidism
Insufficient data
Yes, when used in recommended
doses
Yes, preliminary report
No
Adverse effects have been reported
(Hailer and Benowitz, 2000;
HHS/FDA, 1997; Shekelle et al.,
2003)
Insufficient data
No
Yes, short-term
Yes
Unknown, may cause gastrointestinal
distress and affect absorption of
medications
Insufficient data
Yes
Insufficient data
Insufficient data
No (Pittler et al., 1999; Wuolijoki et al.,
1999)
Likely ineffective (Hallmark et al., 1996;
Lukaski et al., 1996; Trent and Thieding-
Cencel, 1995)
Yes, preliminary report (Blankson et al.,
2000)
Yes, but studies are limited
Yes, appropriate dose arid in combination
with caffeine (Astrup et al., 1992a, 1992b;
Boozer et al., 2001)
Insufficient data, possibly ineffective at dose
of 1,500 mg/d in obese adults (Heymsfield
et al., 1998)
Insufficient data
Yes
Insufficient data
Insufficient data
No
Insufficient data
Insufficient data
similar to other chronic diseases associated with alterations in the biochemistry
of the body. Most other chronic diseases are treated with drugs, and it is likely
that the primary treatment for obesity in the fixture will be the long-term
administration of drugs. Unfortunately, current drug treatment of obesity
produces only moderately better success than does diet, exercise, and behavioral
modification over the intermediate term. Newer drugs need to be developed, and
combinations of current drugs need to be tested for short- and long-term
effectiveness and safety. As drugs are proven to be safe and effective' their use
in less severe obesity and overweight may be justified.
The appropriateness of using weight-loss drugs in the military population
requires careful consideration. On average, a 5 to 10 percent weight loss can
improve comorbid conditions associated with obesity, but it is not known if this
degree of weight reduction by itself would improve fitness or if it could be
expected to improve performance in all military contexts. The side effects that
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106
WEIGHT MANAGEMENT
are sometimes encountered might also restrict the use of weight-loss drugs in
some military contexts. On the other hand, the military is losing or is in danger
of losing otherwise qualified individuals who cannot "make weight." Such
people might be able to keep their weight within regulation if they are allowed
to take weight-loss drugs for the remainder of their term in the military. The
frequency of known side effects of current weight-loss drugs is sufficiently low
that the potential for adverse events would not seem to be a reason to avoid the
use of these drugs by military personnel.
The use of available dietary supplements and herbal preparations to control
body weight is generally not recommended because of a lack of demonstrated
efficacy of such preparations, the absence of control on their purity, and evi-
dence that at least some of these agents have significant side effects and safety
problems. The occurrence of potential adverse effects (e.g., dehydration, mood
alterations) would be of particular concern for military personnel.
SURGERY
Although it would be expected that very few active duty military personnel
would qualify for consideration for obesity surgery, a review of weight-
management programs would not be complete without a discussion of this
option.
For massively obese individuals (those with a BMI above 35 or 40), the
modest weight losses from behavioral treatments and/or drugs do not alter their
obese status. For these individuals, obesity surgery may produce massive, long-
term weight loss. Recent studies have shown dramatic improvements in the
morbidity and mortality of those who are massively obese, and surgery is being
recommended with increasing frequency for these individuals (Hubbard and
Hall, 1991~. Table 4-5 presents the rationale and results of all forms of obesity
surgery.
Individuals who are candidates for obesity surgery are those who (1) exhibit
any of the complications of obesity such as diabetes, hypertension, dyslipidemia,
sleep disorders, pulmonary dysfunction, or increased intracranial pressure and
have a BMI above 35, or (2) have a BMI above 40.
Gastric bypass is currently the most commonly used procedure for obesity
surgery. Following this procedure, patients lose about 62 to 70 percent of excess
weight and maintain this loss for more than 5 years (Kral, 1998; MacDonald et
al., 1997; Pories et al., 1992, 1995; Sugerman et al., 1989~. Biliopancreatic
bypass, another type of obesity surgery, and its variations produce weight losses
comparable or superior to gastric bypass (Kral, 1998~. In addition to massive
weight loss, individuals who undergo obesity surgery experience improvements
in health status relative to hypertension, dyslipidemia, sleep apnea, pulmonary
function (oxygen saturation and oxyhemoglobin levels and decreased carbon
dioxide saturation) (Sugerman, 1987; Sugerman et al., 1986, 1988), obesity-
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES
107
hypoventilation syndrome, and pseudotumor cerebri, urinary incontinence, and
pulmonary dysfunction possibly due to increased intra-abdominal pressure
(Sugerman et al., 1995, 19991.
Obesity surgery is, however, considered the treatment of last resort because
of the short- and long-term complications associated with the surgery. Pe-
rioperative mortality is small but significant (about 0.3 to 2 percent) and appears
to vary inversely with the experience of the surgeon (Kral, 1998~. Other poten-
tial side effects include vomiting, diarrhea, electrolyte abnormalities, liver fail-
ure, renal stones, pseudo-obstruction syndrome, arthritis syndrome, and bacterial
overgrowth syndromes.
THE USE OF STRUCTURED MAINTENANCE PROGRA1\/IS
When to Use a Maintenance Program
The long-term success of weight management appears to depend on the in-
dividual participating in a specific and deliberate follow-up program. Programs
to aid personnel in weight maintenance or prevention of weight gain are
appropriate when:
.
An individual has successfully achieved his or her weight-loss goal and
now seeks to maintain the new weight,
. An individual who is gaining weight has taken a weight-loss readiness
assessment and has determined that he or she is not ready for weight loss at this
time, or
An overweight individual is temporarily excluded from a weight-
reduction program until a medical, physical, or psychological problem stabilizes.
Components of a Maintenance Program
A comprehensive weight-maintenance strategy has five fundamental com-
ponents:
1. It helps the patient select a weight range within which he or she can re-
alistically stay and, if possible, minimize health risks.
2. It provides an opportunity for continued monitoring of weight, food in-
take, and physical activity.
3. It helps the patient understand and implement the principle of balancing
the energy consumed from food with routine physical activity.
4. It helps the patient establish and maintain lifestyle change strategies for
a sufficiently long period of time to make the new behaviors into permanent
habits (a minimum of 6 months has been suggested [Wing, 199811.
5. It considers the long-term use of drugs.
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108
HEIGHT MANAGEMENT
TABLE 4-5 Surgical Procedures Used for Treatment of Obesity in Humans
Procedure
Intestinal resection (Kral, 1989)
Proposed Mechanism
Small intestine malabsorption
Intestinal bypass (Kral, 1998)
Jujuno-ileal bypass (Hallberg et al.,
1975; Kral, 1998; Payne and
DeWind, 1969)
End-to-end, end-to-side (Bray et al.,
1977)
Biblio-pancreatic bypass (Kral, 1998;
Scopinaro et al., 1979, 1998)
Stomach to ileum (Kral, 1998)
Gastric stapling (MacLean et al., 1993)
Gastric bypass (Benotti et al., 1989;
Linner, 1982; Yale, 1989)
Vertical banded gastroplasty (Benotti et
al., 1989; Linner, 1982; Mason, 1982,
Yale, 1989)
Gastric wrapping (Kral, 1998)
. .
Jaw wiring
Subdiaphragmatic truncal vagotomy ~
pyloroplasty (Holle and Bauer, 1978)
Liposuction (Kral 1998)
,
Small intestine malabsorption
Small intestine malabsorption
Small intestine malabsorption
Partial gastric outlet obstruction, limited
food intake
Reduced food intake secondary to very
small stomach size arid restricted flow
rate into small intestine, reduced
intestinal absorption
Reduced food intake secondary to very
small stomach size and restricted flow
rate into small intestine, reduced
intestinal absorption
Reduced food intake secondary to very
small stomach size and restricted flow
rate into small intestine, reduced
intestinal absorption
Prevents solid food consumption
Loss of motor function leads to stomach
distension which causes a feeling of
fullness that may signal the central
nervous system
Removal of subcutaneous fat
" Humoral or neural effects of exposure of ileum to nutrients may lead to increased
effects.
Helping Patients Learn How to Balance Energy
Individuals who have achieved a weight-loss goal generally fall into one of
two groups: those who see no point in participating in a maintenance program
since they believe they know how to keep the weight off and those who remain
open to change and improving their skills in weight management.
The critical role of the health care provider is to motivate the former group
to learn the skills necessary for weight management. The skills necessary to:
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES
109
Results Notes
80% Decrease in energy intake in
immediate postoperative period
Gradual weight increase over 2 years
High failure rate
1 00% Failure
Average weight loss ~ 20 kg
Effects minimal
Considered more effective than vertical
banded gastroplasty and gastric
wrapping, causes dumping, laparoscopic
(leads to decrease in perioperative
complications
Rarely used due to large number of
complications
Procedure abandoned
Cosmetic use only
· Maintain regular exercise for at least 60 minJday or an expenditure of
2,000 to 3,000 kcal/wk (8,368 kJ) (Klem et al., 1997; Schoeller et al., 1997~.
· Decrease the amount of energy-dense foods eaten (especially those that
are low in nutrients).
· Practice healthy eating by including fruits, vegetables, and whole grains
in the diet.
· Understand portion control.
· Access the services of nutrition counselors or other forms of guidance.
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110
Helping Patients Establish Permanent Lifestyle Change Strategies
HEIGHT MANAGEMENT
As mentioned above, individuals who have lost weight need to make per-
manent lifestyle changes in order to maintain their loss. To assist patients in
making these changes, successful maintenance programs will include education
on and assistance with the following factors (Foreyt and Goodrick, 1993, 1994;
Kayman et al., 1990~:
· Self-monitoring. Regular weighing and recording of daily food intake
and physical activity for the first month or two of the maintenance period and
during periods of increased exposure to food (e.g., during the holidays). If
weight gain occurs, reinstitution of this practice may help bring weight back into
control. Frequent follow-up contact with counselors is also crucial (Perri et al.,
19931. Effective follow-up consists of a schedule of regular weekly to monthly
contacts by mail, phone, or in person. Support groups may substitute for some of
this follow-up with a health care provider, but should not replace it.
Physical activity. Daily physical activity is key to successful weight
maintenance; it is the factor cited as the most important in maintaining weight
loss by the majority of individuals in the National Weight Loss Registry (Klem
et al., 1997~. An average of 80 min/day of moderate activity or 35 min/day of
vigorous activity is needed to maintain weight (Schoeller et al., 1997~.
· Problem solving. Learning to identify and anticipate problems that
threaten to undermine success is necessary. Problem solving skills allow the
individual to craft strategies that will resolve problems as they emerge.
· Stress management. Exercise, relaxation, and social support can help
reduce stress. Techniques to reduce stress can be critical for some individuals
who overeat in response to stress.
.
Relapse prevention. Relapse, temporary loss of control, and return to
old behaviors is common. The key to relapse prevention is learning to anticipate
high-risk situations and to devise plans to reduce the damages. Patients need to
learn to forgive themselves for a lapse and view it as a "learning experience."
Reestablishing control is crucial.
.
-= - Or ~
Social infZuence/support. Sabotage by family or friends is seen often
and may be stressful for the individual who is trying to maintain weight. The
skills to recognize intentional or unintentional sabotage may be learned. In ex-
treme cases, a choice may need to be made between the weight-maintenance
program or the relationship. Identifying a fresh circle of supporters or starting a
support group may be useful.
PUBLIC POLICY MEASURES
To the extent that the epidemic of obesity can be attributed to changes in
our living and working environments (the increased availability of calorie-dense
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WEIGHT-LOSS AND MAINTENANCE STRATEGIES
111
foods and decreased opportunity to expend energy), public policy efforts may
help prevent overweight and may assist those who are trying to lose weight or
maintain weight loss (Koplan and Dietz, 19999. Some measures that have been
suggested and/or tried include the following:
· Increasing choices and decreasing prices of low-calorie (and low-fat)
foods (e.g., fruits and vegetables) offered at worksite eating places and in vend-
ing machines (French et al., 1997; Hoerr and Louden, 1993)
· Instituting workplace and community programs that include regular
monitoring, nutrition and health promotion, overweight prevention education,
and exercise classes or groups
· Renovating community spaces to provide more and safer spaces for
physical activity
· Modifying work environments or schedules to encourage greater phys
cal activity on and off the job
· Mandating regular physical activity during the workday (IOM, 1998~.
SUMMARY
,1-
Apart from the obvious need to increase energy expenditure relative to
intake, none of the strategies that have been proposed to promote weight loss or
maintenance of weight loss are universally recognized as having any utility in
weight management. The efficacy of individual interventions is poor, and
evidence regarding the efficacy of combinations of strategies is sparse, with
results varying from one study to another and with the individual. Recent studies
that have focused on identifying and studying individuals who have been
successful at weight management have identified some common techniques.
These include self-monitoring, contact with and support from others, regular
physical activity, development of problem-solving skills (to deal with difficult
environments and situations), and relapse-prevention/limitation skills. However,
an additional factor identified among successful weight managers, and one not
generally included in discussing weight-management techniques, is individual
readiness that is strong personal motivation to succeed in weight management.
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an extremely sensitive area of research, the military could acicIress the question of whether
genetic screening for obesity-prone indivicluals is appropriate for their mission.
Role of Infectious Disease in Obesity
A provocative hypothesis that has been proposer! as an explanation for at least some of the
increase in the prevalence of obesity is that one or more viral infections may produce obesity.
Several animal viruses produce obesity in animals, anti both animal and human viruses have
been associated with obesity in humans (Dhuranc~har et al., 1997, 2000.~.
Although the current committee was not constituted to evaluate this particular issue, it was
presenter! at the committee's workshop and thus is mentioned here as an area where numerous
research questions exist on the role of viruses in the etiology of obesity. Both basic and clinical
studies are needed to identify whether human adenoviruses that have been demonstrated to
produce obesity in animals are associated with obesity in humans.
6-~5
Representative terms from entire chapter:
physical activity
