INTRODUCTION
The treatment of choice for overweight and obese patients is the
combination of diet, exercise, and behavior modification [1].
In carefully selected patients, these modalities may be supplemented by
pharmacotherapy or weight loss surgery. Since behavior modification is a
key component of all weight loss approaches, this chapter will provide
the reader with an overview of behavioral approaches to obesity.
Throughout the chapter, we have indicated Internet sites that provide
further information on given topics or resources for specific patients.
THEORETICAL PREMISE OF A BEHAVIORAL APPROACH
Behavioral approaches to obesity are based on two assumptions: first,
that eating and exercise behaviors are related to body weight and
secondly, that behaviors can be modified by changing both the
antecedents, or cues in the environment, that come before the behavior
and lead to its occurrence, and the consequences, or reinforcers, that
come after the behavior and increase its frequency [2].
Based on these premises, there are three main components to a
behavioral approach, designed to assess the behaviors and to change the
antecedents and consequences controlling the behaviors.
Monitoring the behaviors
In order to determine the behaviors that need to be changed and to
assess progress in making these changes, it is necessary to find a way
to monitor behavior. In weight loss programs, eating and exercise
behaviors are typically monitored by self-report. Patients are asked to
write down all foods consumed and the calories and fat grams in those
foods and all recreational physical activities that are performed.
Although these reports may underestimate intake or overestimate activity
[3], they can be used by the patients and therapist to identify
particular problem areas (e.g. is the participant consuming large
portion sizes, selecting high fat choices, etc.), and to gauge progress.
Changing antecedents
Behavioral approaches assume that the environment is an important
determinant of behavior. Most notably, the physical environment,
including the sight and smell of food, can trigger feelings of hunger
and influence what types of foods are selected. Other types of
environmental cues can also be important. Eating and exercise behaviors
can be influenced by social cues (the behaviors or attitudes of others
around the patient) and by cognitive cues (thoughts and feelings about
eating, exercise and body weight). Thus behavioral approaches include
techniques to change physical, social, and cognitive cues.
Changing consequences/reinforcers
The third key component of a behavioral program is increasing
reinforcers for new, appropriate behaviors. Patients are taught to
recognize small positive changes in their behavior and to reward
themselves verbally and with small tangible rewards for this progress.
Therapist praise and social support from others in the treatment program
are also used as reinforcers.
BRIEF HISTORY OF BEHAVIORAL APPROACHES
Behavioral approaches were first applied to the problem of obesity in
the late 1960’s and early 1970’s [2, 4]. Initial programs were 10-weeks
in length, directed at mildly overweight individuals, and tended to
focus on behaviors such as the time of day and location of eating
episodes, rather than the actual calories consumed. These programs
produced average weight losses of approximately 4.5 kg during the
10-week program. Over time, treatment programs have been lengthened to
20-24 weeks; maintenance interventions have been added; there has been
increased emphasis on physical activity; and both diet and activity have
been viewed in terms of their contribution to calorie balance. With
these newer programs, weight loss has increased to approximately 9-10 kg
at 6 months. Patients maintain about 60-70% of their weight loss (or 5.6
kg) at 1-year follow-up. Table 1 documents the progress over time.
Although modest, the weight losses achieved in behavior modification
program are sufficient to improve cardiovascular risk factors and reduce
the risk of developing diabetes [5, 6]. Positive mood changes have also
been observed in participants in behavioral weight loss programs [7].
|
Table 1. History of Treatment Outcomes in
Behavioral Weight Loss Studies
|
|
1970’s |
1980’s |
1990’s |
| Length of Treatment (wks) |
10 |
14 |
27 |
| Weight Loss (kg) |
4.0 |
7.6 |
9.7 |
| Length of Follow-up (wks) |
22 |
53 |
64 |
| Loss at Follow-up (kg) |
4.0 |
4.8 |
5.6 |
|
Adapted from Wing [1] and Wadden [4]
|
FORMAT OF CURRENT BEHAVIORAL TREATMENT PROGRAMS
Behavioral programs are typically conducted in groups; approximately 15
patients start and complete the program together. Programs are often led
by two co-therapists, with multidisciplinary backgrounds, such as
psychologists, nutritionists, or exercise physiologists. Programs
usually include weekly treatment meetings for 6 months and biweekly or
monthly meetings for the remainder of the year to two years. Behavioral
programs that have included weekly meetings for a full year have been
quite successful, but decreased attendance over time limits the
usefulness of this approach [8, 9].
In some situations, behavioral treatments are offered individually to
patients or using a combination of group and individual approaches. A
recent study [10] suggested that group intervention was more effective
than individual intervention even among patients who expressed a
preference for individual therapy. Group treatment is also clearly less
expensive to provide.
Continued contact is an important component of the maintenance
program. In a program that provided 6-months of weekly treatment and
then no further contact over the subsequent year, patients retained a
weight loss of 4.5 kg, whereas patients in programs that continued to
provide biweekly meetings throughout the year, maintained weight losses
of 13.6 kg [11]. Efforts to provide on-going contact through phone
calls, rather than face-to-face meetings have had inconsistent effects
[12-14]; results may depend on the nature of the calls and specifically
on the amount of therapist involvement and problem solving that is
conducted.
Recently there have been efforts to deliver behavioral treatment
programs via television or the Internet. Two studies of televised
behavioral programs suggest that this approach may be as effective as
face-to-face programs [15, 16]. Tate et al. [17] conducted a randomized
controlled trial of an Internet behavior therapy program. Patients in
the Internet education group (control group) were helped to identify
appropriate web sites related to diet, exercise, and weight management.
For patients in the Internet behavior therapy program, this educational
material was supplemented by treatment lessons, weekly e-mail contact
between patients and the therapist (patients submitted a diary of their
weekly calorie intake, exercise, and weight and the therapist provided
supportive feedback) and a bulletin-board for sharing of information.
The Internet education group lost 1.6 kg at 6 months, compared to 4.1 kg
in the Internet behavior therapy group.
CONTENT OF BEHAVIORAL TREATMENT PROGRAMS
The content of behavioral treatment programs has become relatively
standardized. Group sessions typically include an individual, private
weigh-in, review of self-monitoring records, and then a presentation of
the lesson for the week. Participants are given specific assignments to
complete over the subsequent week, which are then reviewed at the
following lesson. Table 2 identifies some of the topics typically
addressed in a behavioral program.
Table
2. Standard Behavioral Treatment Sessions |
| Getting Started |
Presents an overview of behavioral
approach. Prescribes a 1-2 lb/week weight loss goal and an
individual calorie goal to achieve this weight loss. |
| Self-Monitoring |
Teaches the importance of recording
immediately and, honestly. Helps patients learn to find calorie
values by using a reference book and reading food labels. |
| Modifying Diet |
Emphasizes the importance of
restricting dietary fat intake. Teaches common sources of
dietary fat and strategies to lower fat. |
| Increasing Physical Activity |
Introduces the importance of physical
activity for energy balance and prescribes activity goals that
gradually increase over the course of the program. |
| Stimulus Control |
Teaches patients to remove cues for
inappropriate behaviors and increase cues for appropriate
behaviors. |
| Changing the Act of Eating |
Stresses the importance of eating
slowly, eating in designated locations, and eating a variety of
different foods. Often incorporates discussion of the food guide
pyramid. |
| Problem Solving |
Teaches patients to identify problem
areas or barriers related to eating or exercise, to brainstorm
solutions to their problems, and then select one to implement. |
| Social Support |
Helps patients to learn to ask others
for the type of support they need to change their behaviors. |
| Restaurant Eating |
Presents strategies for managing
eating away from home. |
| Changing Cognitions |
Teaches patients to recognize their
negative thoughts and counter them with positive re-framing. |
| Managing Stress |
Helps patients learn to identify
sources of stress in their lives, examine the association
between stress and eating, and develop new strategies for
dealing with stress. |
| Motivational |
Teaches patients to develop
motivational strategies to help them maintain their habit
changes long-term. |
| Relapse Prevention |
Presents the Malatt and Gordon
Relapse Prevention Model [18]. Teaches patients to recognize
high risk situations, plan for these situations, and to keep
lapses from leading to relapse. |
SETTING WEIGHT LOSS GOALS
The NHLBI Clinical Guidelines on the Identification, Evaluation, and
Treatment of Overweight and Obesity in Adults-The Evidence Report [1]
recommends that individuals with a BMI >25 (overweight) and those
with a BMI >30 (obese) be counseled on the importance of weight
management. Cardiovascular risk factors should be assessed, and weight
loss recommended in those with a BMI >30 or a BMI 25-29.9 or waist
circumference >80 cm (F) or > 102 cm (M) AND > 2 risk factors.
The initial goal of therapy should be to achieve a 10% reduction in
body weight. Patients should be encouraged to lose 1-2 lb/week and thus
Recent studies suggest that patients often desire to achieve much
greater weight losses than this 10% goal [19]. What patients report as a
“dream” weight would be accomplished by a 38% reduction in
body weight; a weight that would make them happy, would be accomplished
by a 31% reduction in weight; a weight that would be
“acceptable” would be accomplished by a 25% weight loss, and a
weight that they would be disappointed to achieve would be accomplished
by a 15.7% weight loss. Since currently even our most effective
behavioral weight loss programs achieve outcomes below this level, it is
important to counsel patients on achievable weight losses and attempt to
reduce the discrepancy between the desired and the achievable outcomes.
should be able to achieve 10% reduction within the first 6 months of
treatment. Subsequently, efforts should be directed at maintaining the
weight loss.
Recent studies suggest that patients often desire to achieve much
greater weight losses than this 10% goal [19]. What patients report as a
“dream” weight would be accomplished by a 38% reduction in
body weight; a weight that would make them happy, would be accomplished
by a 31% reduction in weight; a weight that would be
“acceptable” would be accomplished by a 25% weight loss, and a
weight that they would be disappointed to achieve would be accomplished
by a 15.7% weight loss. Since currently even our most effective
behavioral weight loss programs achieve outcomes below this level, it is
important to counsel patients on achievable weight losses and attempt to
reduce the discrepancy between the desired and the achievable outcomes.
Self-monitoring Weight
Behavioral weight control programs typically weigh patients at every
group meeting and record this information. In addition, patients are
instructed to weight themselves at home at regular intervals, either
daily or at least once a week. Data from the National Weight Control
Registry suggest that successful weight losers monitor their weight
quite closely [20]. Forty-five percent of registry participants weigh
themselves at least daily and 31% report weighing themselves at least
once a week. This frequent monitoring allows them to promptly take steps
to correct any small increases in weight that they observe.
MODIFYING DIETARY INTAKE
Dietary prescriptions in behavioral programs
Behavioral programs attempt to change energy balance by influencing both
calorie intake and calorie expenditure. Most programs emphasize
decreasing overall calorie intake and restricting fats specifically. At
the start of the program, participants are assigned a calorie goal
designed to produce a 1-2 lb/week weight loss. This may be done on an
individual basis, by estimating current calorie intake and then
subtracting 500 to 1000 kcal/day. In some studies current intake is
estimated by multiplying the patients’ weight in pounds by 12, and in
others resting energy expenditure is estimated and an adjustment made
for the patients’ activity level. Alternatively in many programs,
participants are simply assigned a calorie goal depending on their
initial body weight (e.g. patients < 200 lb may be asked to eat
1000-1200 kcal/day and those > 200 lb may be asked to eat 1500
kcal/day).
Very low calorie diets, which are diets of <800 kcal/day, were
extremely popular in the 1980’s [21]. These diets are usually consumed
as liquid formula or lean meat, fish and fowl. Patients were found to
lose an average of 9 kg in 12 weeks on these regimens. However, after
stopping the diet, regain was common. Therefore, several studies were
designed to examine the combination of very low calorie diets and
behavior modification, reasoning that VLCD might increase initial weight
loss and the behavioral strategies might improve maintenance of weight
loss [8, 9]. This reasoning was supported in part; the combination of
behavior modification plus VLCD was found to be more effective than VLCD
alone. However, behavior modification plus VLCD was not more effective
than behavior modification with a low calorie diet (1200-1500 kcal/day).
Combining behavior modification with a VLCD increased initial weight
loss, but despite the behavioral training, these patients still regained
large amounts of weight over the year of follow-up so that at the end of
the study (2-year follow-up), weight losses of patients treated with
VLCD did not differ from patients with low calorie diets. Given these
results, along with concern about health consequences of rapid weight
loss, the expense of using VLCDs, and the evidence that weight losses
are comparable on liquid diets of 400, 600 and 800 kcal/day, most weight
loss programs now use higher calorie levels (>800 kcal/day).
Many behavioral programs encourage patients not only to reduce their
overall calories, but also to lower their fat intake to 20-30% of their
calories in order to improve weight loss and lipid responses to weight
loss. The combination of restricting dietary fat and calories has been
shown to be more effective then fat restriction alone [22] or calorie
restriction alone [23, 24]. Moreover, reducing fat intake and decreasing
consumption of specific high fat food (beef, hot dogs, cheese, French
fries, sweets) have been shown to be related to maintenance of weight
loss [25, 26]. For simplicity, participants are given a fat goal in
grams of fat/day (e.g. participants on a 1200 kcal diet are instructed
to consume 27-40 grams of fat for a diet of 20% – 30% fat).
Dietary Intake in Successful Weight Losers
The National Weight Control Registry is a registry of over 3,000
individuals who have lost at least 30 lb (mean = 66 lb) and kept it off
at least 1 year (mean = 6 years). These individuals are asked to
complete questionnaires about their diet, exercise, and general weight
control behaviors. Although these individuals report having lost weight
in a variety of ways (50% lost weight on their own and 50% lost weight
with the help of a program, physician, or counselor), there seem to be
certain commonalties in their weight maintenance behaviors [20, 27]. Of
particular interest is the fact that these individuals report that they
continue to eat a diet that is low in calories (1380 kcal/day) and low
in fat (24% of calories from fat). Almost 80% of participants report
eating breakfast every day during the week and only 4% reported never
eating breakfast. Despite the recent popularity of diets recommending
low carbohydrate intake, less than 1% of registry participants reported
consuming <24% of their diet as carbohydrate (< 90 g of
carbohydrate on a 1500 kcal regimen).
Strategies for Modifying Dietary Intake
Self-Monitoring Calorie and Fat Intake. Participants in
behavioral programs are instructed to record all food and beverages they
consume and the calories and fat grams in those foods. By tallying their
fat and calorie intake after each meal, participants can gauge the
amount remaining for later meals. Such self-monitoring is prescribed
daily for the first 6 months of the program and at least one week per
month subsequently. Continued self-monitoring of intake is one the
strongest predictors of maintenance of weight loss [28, 29].
Improving the quality of foods selected. Patients in
behavioral weight loss programs are encouraged to select foods that will
provide the greatest nutritional benefit for the fewest calories. The
emphasis in on decreasing overall intake of fat. Strategies are provided
for improving quality of foods consumed at home and when eating out. For
example, patients are taught to substitute lower calorie items for
higher calorie alternatives, to restrict use of fat in cooking and
flavoring of foods, and to modify favorite recipes for healthier eating.
Providing Increased Structure Regarding Diet. There have been several
recent studies suggesting that providing structure to patients on what
they should eat, and thereby simplifying choices, preparation time,
etc., can be very helpful in promoting dietary adherence [30-32].
Patients who were given a box of food containing exactly what they
should eat for 5 breakfasts and 5 dinners each week had better weight
losses at 6, 12 and 18 months (10.1, 9.1, 6.4 kg, respectively) than
patients who were given the comparable calorie and fat goals for these
meals but selected the foods on their own (7.7, 4.5, and 4.1 kg,
respectively) [30]. Providing patients with a specific meal plan,
indicating exactly what should be eaten for each meal and a grocery list
to purchase these items, was also more effective than simply allowing
patients to self-select their diet [31]. Providing such meal plans or
the actual food to patients appears to remove some of the barriers to
dietary adherence, promotes more regular meal consumption and fewer
snacks, and positively affects the types of foods stored in the home.
Similar positive results have been obtained using prepackaged entrees
for all or part of the diet and using Slimfast [33]. In all of these
regimens, patients are eating 900-1500 kcal/day suggesting that it is
the structure, rather than an extremely low calorie level that makes
these approaches effective.
MODIFYING PHYSICAL ACTIVITY
There have been a large number of randomized controlled trials
comparing the effects on weight loss of diet only, exercise only, and
the combination [1, 34]. These studies suggest that exercise alone has
very small effects on body weight, and that adding exercise to a diet
program increases initial weight loss by approximately 2 kg. These
modest effects of exercise may well be due to the low dose of exercise
used in many of these trials and the short duration of the studies. The
greatest benefits of exercise are seen in the maintenance of weight
loss. Of 6 studies that have examined long-term weight losses in diet
only versus diet plus exercise, all 6 found that the latter had better
outcomes, although in many of these studies the difference was not
statistically significant [34]. Correlational data are even stronger in
suggesting the benefits of long term physical activity for maintenance
of weight loss [35].
Prescribing exercise in a behavioral weight loss program
Participants in behavioral weight loss programs are encouraged to
increase their physical activity slowly, in order to avoid injury, and
to check with their physician before undertaking strenuous activity. The
goal for physical activity varies across programs, but often
participants are instructed to gradually increase their activity until
they achieve a level of at least 1000 kcal/week. Participants are able
to choose exactly what types of exercise they enjoy, but most use
walking for the majority of their activity. A good rule of thumb is that
walking 1 mile will burn approximately 150 kcal (heavier patients will
burn more calories). Calories from other types of activities are
available in many textbooks, patient guides and on the Internet.
Alternatively patients may be assigned a goal of achieving at least 150
minutes/week of physical activity, using brisk walking or activities of
similar intensity to brisk walking.
There have been two recent studies comparing programs that involve
home-based physical activity and those that include supervised exercise
programs [36, 37]. In these studies, all patients received the same diet
and behavioral instruction and the same exercise goals, but the programs
differed in the format used to achieve the physical activity. Both
studies found no differences in short-term weight loss, but the
maintenance of weight loss was better with home-based exercise than with
supervised activity. The advantage of the former may be the freedom to
exercise whenever, wherever, and however the participant chooses.
The focus in behavioral programs is typically aerobic exercise, but
Wadden and colleagues recently examined resistance training and the
combination of resistance training and aerobic exercise [38, 39]. These
investigators found no difference in weight losses achieved with the
various types of exercise. Again selecting activities that patients
enjoy and combining a variety of different types of exercise is
recommended.
Physical Activity in Successful Weight Losers
Data from the National Weight Control Registry, described above,
highlights the importance of physical activity for weight loss
maintenance [20]. In the NWCR, 91% of individuals report that physical
activity was one aspect of their maintenance of weight loss. On average,
women in the registry report expending 2545 kcal/week in exercise and
men report 3293 kcal/week. These data suggest that successful weight
losers are exercising over an hour a day.
Physical Activity Goals
The high exercise level reported by NWCR members has raised the
question of whether participants in weight loss programs should be
encouraged to achieve higher activity levels, than typically
recommended, e.g. 2500 kcal/week, rather than the usual 1000 kcal/week
goal. This suggestion is supported by several other studies. Jakicic et
al. [40] reported better weight loss maintenance in patients who
exercised > 200 minutes per week and Jeffery and Wing [41] found that
patients in the highest quartile of exercise, who expended over 2500
kcal/week, had better weight loss maintenance then those with lower
levels of activity. A randomized controlled trial [42] comparing 1000
kcal/week and 2500 kcal/week prescriptions is currently ongoing; at
month 18, weight loss in the high exercise condition were significant by
greater than the low exercise condition (6.7 kg vs. 4.1 kg). Thus, while
the initial goal of behavioral programs should be 1000 kcal/week (or 150
minutes/week), it is recommended that patients progress to higher goals
over time.
Strategies to Modify Physical Activity
Self-Monitoring Physical Activity. Participants in behavioral
programs are instructed to record all activities they complete. To
simplify recording, they are usually instructed to focus only on
exercise bouts that last at least 10 minutes. Patients record either
calories used in activity or minutes of activity.
Increasing Lifestyle Activity. Modern civilization has evolved
to a point where there are many devices designed to save energy
expenditure, most notably automobiles, remote controls, and escalators.
Patients in behavioral weight loss programs are helped to identify these
energy saving devices and to plan ways in which they can expend more
energy in their daily activities, e.g. parking further from the store,
using stairs, getting off the bus one stop earlier. Although these
lifestyle behavior changes can add up over time to significant increases
in energy expenditure, they are difficult to quantify and hard to record
in self-monitoring diaries. Therefore such lifestyle activities are
viewed as a supplement to a longer, more structured activity/exercise
bouts.
Dividing exercise into multiple short bouts. The number one
barrier to exercise is lack of time. To address this problem, patients
may find it easier to exercise for multiple 10-minute bouts rather than
one 40-minute bout. Several studies have examined this issue [40, 43].
In a study by Jakicic et al. [40], patients were randomly assigned to
exercise in one 40-minute bout/day, 5 days/week or to complete four
10-minute bouts on each of the 5 days. All other aspects of the weight
loss programs were identical in the two conditions. The short-bout
program produced better initial adherence and comparable long-term
changes in weight and cardiovascular fitness to the long-bout program
[40]. Thus, exercising in multiple bouts may be a useful option for some
participants.
Decreasing sedentary activities such as TV time. There have
been several studies in children that show that decreasing the number of
hours/week of sedentary activities (TV, computer games) may be an
effective approach to weight control [44, 45]. Epstein and colleagues
[44]compared the effects of increasing physical activity, decreasing
sedentary behavior, and the combination of the two in a study of
overweight children aged 8-12. The children who were asked to decrease
sedentary time had the best long-term weight control outcome, and
comparable improvements in fitness to the other conditions. These
results suggest that as the children decreased sedentary activities they
adopted other more physically active pursuits (and thus improved
fitness). It is not known whether this approach would be as effective
with adults as it was with children.
Decreasing barriers for physical activity. Maintenance of
physical activity is key for long-term weight loss [34, 35], but it is
difficult to motivate patients to continue to be physically active
long-term. Behavioral programs teach patients strategies for dealing
with common barriers to exercise, e.g. exercising in hot weather or cold
weather; appropriate stretching exercises to prevent injuries.
Motivation for physical activity is increased by encouraging patients to
do a variety of different activities that they enjoy and helping
patients recognize the improvements in fitness that occur with regular
exercise.
CONCLUSIONS
Behavioral approaches are used to help patients make long-term
changes in their eating and exercise behaviors. To accomplish this,
behavioral approaches stress monitoring of dietary intake and physical
activity and modifying the cues and reinforces in the environment.
Better results have been achieved in behavioral programs that provide
longer periods of treatment contact, more structured approaches to
modifying dietary intake and higher goals for physical activity.
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