Dieting Status and Its Relationship to Weight, Dietary Intake, and Physical Activity Changes Over Two Years in a Working Population

The present study prospectively examined changes in dietary intake, physical activity and weight associated with self-reported efforts to lose weight in a cohort of 3671 men and women sampled from the general population. Dieting efforts, dietary intake, physical activity and weight were measured at two points in time, 24 months apart. At baseline, current dieters reported consuming fewer dairy products, sweets, meat, soft drinks and fried potatoes (all p's < .0001), and engaging more frequently in high-intensity physical activity (p < .0001) than those not currently dieting. At follow-up, current dieters reported consuming fewer sweets (p < .0001) and fried potatoes (p < .0008), and engaging more frequently in moderate-intensity physical activity (p < .02) than those not currently dieting. Prospectively, those who initiated weight-loss diets showed the largest decrease in consumption of sweets (p < .0001), soft drinks (p < .0001), and fried potatoes (p < .01), and increase in frequency of high-intensity physical activity (p < .0001) and moderate-intensity physical activity (p < .007). Those initiating weight-loss diets were the only group to lose weight (1 lb.). Those dieting at baseline but not at follow-up gained the most weight (4 lbs.). Self-reports of current dieting correspond to reported changes in dietary intake and physical activity, and to measured changes in weight over the same time period. Individuals who report dieting to lose weight have healthier eating and exercise patterns than those who do not report dieting.

Dietary and Physical Activity Correlates of Long-Term Weight Loss

Covariations in body mass index (BMI), physical activity, macronutrient intake, and the frequency of consumption of specific foods were examined among 82 men and 75 women participating in a behavioral weight loss program over a period of 18 months. Results of repeated measures analyses of covariance showed that BMI change was inversely related to change in physical activity and change in frequency of vegetable consumption. BMI change was positively related to change in calorie intake from fat and change in frequency of consumption of beef, hot dogs, and sweets. Change in fat calories predicted BMI change better than change in total calories. In addition, change in the frequency of consumption of specific foods accounted for a larger percentage of the variance in BMI change than did change in macronutrients (10.4% vs. 5.2%). No differences were found between predictors of weight loss vs. weight maintenance.

Mail and phone interventions for weight loss in a managed-care setting: weigh-to-be 2-year outcomes

OBJECTIVE

Evaluate effectiveness of weight-loss interventions in a managed care setting.

METHODS

Three-arm randomized clinical trial: usual care, mail, and phone intervention. Participants were 1801 overweight managed care organization (MCO) members. Measures included baseline height, weight at baseline and 24 months, self-reported weight at 18 months. Intervention and participation in other weight-related programs was monitored across 24 months.

RESULTS

Weight losses were 2.2, 2.4, and 1.9 kg at 18 months in the mail, phone, and usual care groups, respectively. Mail and phone group weight changes were not significantly different from usual care (P<0.35). Weight losses at 24 months did not differ by condition (0.7 kg mail, 1.0 kg phone, and 0.6 kg usual care, P=0.55). Despite treatment availability over 24 months, participation diminished after 6 months. Participation was a significant predictor of outcomes in the mail and phone groups at 18 months and the mail group at 24 months. Cost-effectiveness of phone counseling was $132 per 1 kg of weight loss with mail and usual care achieving similar cost-efficiency of $72 per 1 kg of weight loss.

CONCLUSION

Although mail- and phone-based weight-loss programs are a reasonably efficient way to deliver weight-loss services, additional work is needed to enhance their short- and long-term efficacy.

Weight loss goals and treatment outcomes among overweight men and women enrolled in a weight loss trial

Participants in weight loss programs typically set unrealistically high weight loss goals that some believe are detrimental to success. This study examined outcomes associated with goal and ideal body mass index (BMI). Participants (N=1801) were enrolled in a weight loss trial comprised of low-intensity mail or telephone interventions vs usual care. Goal and ideal weight losses were assessed by asking participants how many pounds they expect to lose in the program (goal) and how much they would like to weigh (ideal). Goal and ideal weight losses were unrealistically high (men: -16 and -19%, women: -21 and -27%). For women, less realistic goals were associated with greater weight loss at 24 months. Goals were not associated with participation or weight loss for men. Results are more supportive of the idea that higher goals motivate women to lose weight than of the hypothesis that high goals undermine effort.

The comparative and cumulative effects of a dietary restriction and exercise on weight loss

OBJECTIVE

To assess the independence of changes made in diet and physical activity for weight loss; and, to examine the comparative and cumulative effects of these behavioral changes on weight loss outcomes.

DESIGN

The observational study is based on longitudinal data collected from 674 women and 288 men enrolled in a 2-year weight loss program introduced into a managed care setting.

MEASUREMENTS

The outcome variable was body mass index (BMI) change from baseline to 2-year follow-up. Primary independent variables were changes in physical activity and dietary fat intake, assessed as continuous measures using the Paffenbarger Physical Activity Questionnaire and Block Fat Screener Questionnaire, respectively. Two-way ANCOVA was used to assess the relative effect on BMI of behavioral changes.

RESULTS

Study results showed no preference for diet or physical activity change as a weight loss strategy. For both genders, the relationship between the two behaviors was synergistic rather than compensatory. Examination of the comparative benefits of behavioral changes indicated that, for women and men, restricting fat intake was more effective than increasing exercise for weight loss. While fat restrictions alone contributed to weight loss in both genders, exercise alone provided weight loss benefits to men, only. The cumulative effect of weight loss behaviors varied by gender. In women, an interaction was observed. The response of weight to fat restriction was greater among those who increased their exercise moderately or substantially. In men, there was no interaction; exercise increases helped to offset weight gain or provided small weight loss benefits at all levels of dietary fat change.

CONCLUSION

Dietary changes appeared to be more effective than increased physical activity for weight loss. For women, the cumulative effect of concomitant changes in diet and exercise on weight loss was more than additive.

Relationship between changes in food group variety, dietary intake, and weight during obesity treatment

BACKGROUND

Experimental studies show diets with greater variety in energy-dense foods increase consumption and body weight. Reducing variety in energy-dense food groups may decrease energy and dietary fat intake, promoting weight loss.

OBJECTIVE

This study examined changes in food group variety during obesity treatment and the relation between changes in food group variety, dietary intake, and weight.

DESIGN

Overweight men and women (n=202) were randomly assigned to one of two standard behavioral treatments with varying exercise prescriptions (exercise level of 4186 kJ/week (1000 kcal/week) or 10465 kJ/week (2500 kcal/week)), but received the same diet. Complete measures were obtained from 122 participants, of which 70 (58%) were female, with a mean body mass index of 31.3 kg/m(2) (s.d.=2.5).

MEASUREMENTS

Food group variety and diet composition were assessed at 0, 6, and 18 months from food-frequency questionnaires. Food group variety was calculated as percent of foods consumed on a weekly basis within a food group, irrespective of servings consumed.

RESULTS

Participants reported increased variety (P</=0.001) in low-fat breads (LFB) and vegetables, and decreased variety (P</=0.001) in high-fat foods (HFF), and fats, oils, and sweets (FOS) over the course of the 18-month study. From 0 to 6 months, decreased HFF and FOS variety was associated with reduced energy and percent dietary fat intake, and decreased HFF variety was related to weight loss. From 6 to 18 months, decreased HFF variety and increased LFB variety was associated with reduced percent dietary fat consumed and weight loss.

CONCLUSION

Changing variety in specific food groups may help in adopting and sustaining a diet low in energy and fat, producing better weight loss and weight loss maintenance.

Binge eating disorder, weight control self-efficacy, and depression in overweight men and women

OBJECTIVE

To examine binge eating, depression, weight self-efficacy, and weight control success among obese individuals seeking treatment in a managed care organization.

DESIGN

Gender-stratified analyses of associations between binge eating, depression, weight self-efficacy, and weight change, using data from a randomized clinical trial that compared low-cost telephone-based, mail-based, and usual care interventions for weight loss.

SUBJECTS

A total of 1632 overweight individuals (460 men, 1172 women; mean age: 50.7 y; mean body mass index: 34.2 kg/m(2)) were recruited from a large Midwestern US managed care organization.

MEASUREMENTS

Height and weight were measured by study personnel at baseline, and self-reported weight was assessed at 6 and 12 months; self-reported depression status, binge eating, and self-efficacy for weight control were assessed at baseline.

RESULTS

Lifetime prevalence rates for depression and probable binge eating disorder were high. Weight self-efficacy was inversely related to weight in both men and women. For women, depression was associated with lower weight self-efficacy and higher body weight. Women reporting depression or lower weight self-efficacy at baseline had less weight loss success at 6 and 12 months. Depression, binge eating disorder, and weight self-efficacy were not significantly associated with weight loss success in men.

CONCLUSION

Negative emotional states are highly prevalent and predict poor treatment outcomes, particularly for obese women. As obese women with clinical depression typically are excluded from intervention studies, further research on how to address the intersection of obesity intervention and mood management may be warranted.

Mail and phone interventions for weight loss in a managed-care setting: Weigh-To-Be one-year outcomes

OBJECTIVE

To describe methods, recruitment success, and 1-y results of a study evaluating the effectiveness of phone- and mail-based weight-loss interventions in a managed care setting.

DESIGN

Randomized clinical trial with three groups, that is, usual care, mail intervention, and phone intervention.

SUBJECTS

In total, 1801 overweight members of a managed-care organization (MCO).

MEASUREMENTS

Height, weight, medical status, and weight-loss history were measured at baseline. Participation in intervention activities was monitored for 12 months in the two active treatment groups. Self-reported weight was obtained at 6 and 12 months.

RESULTS

More individuals assigned to mail treatment started it (88%) than did those assigned to phone treatment (69%). However, program completion rates were higher in the phone (36%) than mail (7%) intervention. The mean weight losses were 1.93, 2.38, and 1.47 kg at 6 months in the mail, phone, and usual care groups, respectively. The differences between the phone and usual care groups were statistically significant. The mean weight losses at 12 months did not differ by treatment group (2.28 kg mail, 2.29 kg phone, and 1.92 kg usual care). Greater weight loss was seen in men, older participants, and those with no prior experience in a weight-loss program. Heavier participants and those who reported current treatment for depression lost less weight.

CONCLUSION

Although mail- and phone-based weight-loss programs can be delivered to large numbers of people in an MCO setting, additional work is needed to enhance their clinical efficacy as well as to assess their costs.

Strength training for obesity prevention in midlife women

OBJECTIVE

The primary goal of this study was to assess whether increases in fat-free mass (FFM) and decreases in total and percentage fat mass from 15 weeks of twice weekly supervised strength training would be maintained over 6 months of unsupervised exercise in a randomized controlled trial.

DESIGN

In all, 60 women aged 30-50 y, body mass index between 20 and 35 kg/m(2), were randomized to control or treatment groups. The treatment group performed twice-weekly supervised strength training followed by 6 months of unsupervised training. Measurements at baseline, 15, and 39 weeks included body weight and body composition by dual-energy X-ray absorptiometry. Repeated measures regression was used to assess between-group differences for changes over time.

RESULTS

Almost 90% of prescribed exercise sessions were completed. The body composition treatment effects over 15 weeks were largely maintained over 6 months of unsupervised exercise. Over the total 39 weeks of strength training, the treatment group gained +0.89 kg more in FFM, lost -0.98 kg more in fat mass, and lost -1.63% more in percent body fat when compared to the control group. P-values for these between-group differences in 39-week changes were 0.009, 0.06, and 0.006, respectively. Strength training did not result in any significant weight loss or waist circumference attenuation. Adjustment for changes in energy intake and physical activity did not alter these results.

CONCLUSIONS

Twice-weekly strength training is behaviorally feasible for busy midlife women and the favorable body composition changes resulting from supervised strength training can be maintained over time. These findings lay the groundwork for determining the long-term health benefits of this behaviorally feasible exercise prescription, potentially including prevention of age-associated fat gains.

The Challenge study: theory-based interventions for smoking and weight loss

Both smokers and overweight persons report frequent efforts to change their behavior. Long-term success, however, is achieved by few. Interventions are needed to improve long-term success in smoking cessation and weight loss. Our research program is designed to address this need and to test a novel conceptualization of health behavior change that is based on the premise that the initiation and the maintenance of behavior change involve different decision processes. Positive expectations about the consequences of behavior change are thought to guide decisions to initiate behavior change, whereas satisfaction with the outcomes afforded by one's behavior guides decisions about maintenance. In the first phase of our research program, we are evaluating the effect people's expectations about the benefits of behavior change have on immediate and long-term behavioral outcomes. Specifically, participants are assigned to either an 'optimistic' treatment condition that emphasizes positive expectations for outcomes or a 'balanced' treatment condition that gives equal weight to the benefits and costs associated with behavior change. The impact of manipulating people's expectations about behavior change will be examined in the areas of smoking cessation and weight loss. Results of these studies will advance research on health behavior change by informing practical and theoretical understanding of the factors that control decisions to initiate a new pattern of behavior and to maintain it.

Prevalence and correlates of large weight gains and losses

OBJECTIVE

To examine the prevalence and correlates of large weight gains and losses over a 3 y period in a heterogeneous population of participants in a study of weight gain prevention.

DESIGN AND MEASURES

Analyses based on a cohort of 823 participants in a weight gain prevention study whose weight was measured on at least two of four annual examinations.

RESULTS

Weight gains and losses of >or=5% body weight over 1 y were observed in 9.3 and 15% of the population, respectively. Weight gains among those initially losing weight were significantly greater (3.9 kg) than among those experiencing stable weight (0.8 kg) or a large weight gain (1.5 kg) over the following 2 y. Cumulative weight changes over 3 y were -2.6, 1.0 and 7.6 kg among large loss, weight stable and large gain groups, respectively. Large weight loss was more common in smokers, large gains were more common in younger people and in those with a more extensive weight loss history, and stable weight was observed more often in individuals with less extensive histories of weight loss.

CONCLUSION

The high prevalence of large short-term weight gains and losses in this heterogeneous population, their apparent resistance to short-term reversal, and the strength of their relationship to longer-term weight trends suggest that rapid weight change over relatively short time intervals is a phenomenon that deserves more research attention. Short periods of rapid weight gain may contribute importantly to rapidly rising obesity rates.

Using signs, artwork, and music to promote stair use in a public building

OBJECTIVES

This study assessed the impact on stair use of improving the attractiveness of a stairwell.

METHODS

Observations of stair usage were made in a university building during baseline, 2 interventions, and follow-up. The first intervention involved signs; the second intervention added artwork and music in the stairwell.

RESULTS

More participants used the stairs during the music and artwork intervention than at baseline or when signs alone were used.

CONCLUSIONS

Improving the aesthetic qualities of a stairwell can increase rates of stair usage in a public building. Designs for buildings should take accessibility and aesthetic issues into consideration.

Food provision as a strategy to promote weight loss

Intervention strategies used in weight-control programs typically rely on participants to make behavior changes on their own. Better results might be achieved if more direct approaches were taken to make environmental changes by providing food to participants and paying them for weight loss. Two studies on food provision for improving weight loss were conducted. The first study used a five-group design contrasting no treatment, standard behavior therapy (SBT), SBT plus food provision, SBT plus financial incentives, and SBT plus food provision and incentives. At 6, 12, and 18 months, weight losses in the two groups receiving food provision were significantly greater than in the two groups without food provision. The incentives did not affect weight loss. To better understand the reasons for the success of food provision a second study was conducted comparing SBT, SBT plus menus, SBT plus food provision with a copay, and SBT plus free food. Groups 2, 3, and 4 all had better weight losses than SBT and did not differ from each other at the end of the 6-month treatment and at the 18-month follow-up. Food provision and menus were associated with increased behavior compliance, increased nutrition knowledge, more regular meals and fewer snacks, reduced barriers to weight loss, and improved quality of foods in participants' homes. Food provision seems to be a useful strategy for promoting weight loss.

Environmental influences on eating and physical activity

Obesity has increased dramatically over the past two decades and currently about 50% of US adults and 25% of US children are overweight. The current epidemic of obesity is caused largely by an environment that promotes excessive food intake and discourages physical activity. This chapter reviews what is known about environmental influences on physical activity and eating behaviors. Recent trends in food supply, eating out, physical activity, and inactivity are reviewed, as are the effects of advertising, promotion, and pricing on eating and physical activity. Public health interventions, opportunities, and potential strategies to combat the obesity epidemic by promoting an environment that supports healthy eating and physical activity are discussed.

Understanding weight stigmatization: a focus group study

OBJECTIVES

The purpose of this research was to investigate, in a nonclinical sample of adults, thoughts on and experiences with weight stigmatization.

DESIGN

Focus groups were used to collect information. Participants were recruited through a newspaper advertisement and flyers posted in public places in Minneapolis and St. Paul. During the focus groups, participants were led in a discussion about their thoughts on weight stigmatization and personal experiences of being treated differently or poorly because of their weight.

SUBJECTS

Six gender-specific focus groups consisted of 31 adult volunteers (17 women and 14 men).

VARIABLES MEASURED

Perceptions of weight-based stereotypes and weight stigmatization and personal reports of having been treated differently or poorly owing to weight were measured.

RESULTS

Participants reported a variety of experiences of being treated differently or poorly because of their weight. These included teasing, harassment, slurs and insults, negative judgments and assumptions, and perceived discrimination. Participants reported that such experiences occurred at home, among friends and strangers, at work, and in health care settings. Women reported a greater number and a greater variety of negative experiences than men.

IMPLICATIONS

The results indicated that participants experienced weight-based stigmatization in many aspects of their lives. Awareness of these experiences may assist in the development of treatments for overweight individuals.

Public health strategies for obesity treatment and prevention

OBJECTIVE

To review research on public health interventions for obesity.

METHODS

Describe recent changes in obesity prevalence in the United States and 5 research studies from the University of Minnesota directed at the problem.

RESULTS

The prevalence of obesity has increased dramatically over the last 15 years.

CONCLUSIONS

Recent increases in obesity in the United States have been of great concern for public health. Health education approaches to addressing the problem have not been effective. It is suggested that alternative approaches, such as changing the price structure of foods, may be necessary if the problem is to be successfully addressed.

The relationship between restraint and weight and weight-related behaviors among individuals in a community weight gain prevention trial

PURPOSE

The present study evaluated the cross-section and prospective associations between the Eating Inventory's (EI) total, flexible and rigid dietary restraint scales and changes in weight and behaviors in a community sample of adults enrolled in a 3 y weight gain prevention study.

METHODS

Subjects were participants in the Pound of Prevention (POP) study, a community-based weight gain prevention trial.

RESULTS

Higher levels of baseline total, flexible and rigid dietary restraint were related to lower weight and more weight-controlling behaviors at the baseline assessment. Baseline restraint measures positively predicted increases in weighing frequency over the 3 y follow-up. Increases in restraint over the follow-up period were related to decreases in weight, energy intake and television watching, and increases in self-weighing and physical activity.

CONCLUSION

The EI's total, flexible and rigid restraint scales were not differently associated with weight and behaviors in this heterogeneous sample of adults who were attempting to lose weight. Developing methods to increase behavioral and cognitive strategies to control weight may help to prevent weight gain in clinical and community samples.

The behavioral determinants of exercise: implications for physical activity interventions

In light of the well-documented health benefits of physical activity and the fact that the majority of adult men and women are inactive, promoting regular physical activity is a public health priority. This chapter reviews current research findings regarding the determinants of exercise behavior. It also discusses the implications of this knowledge for individual and public health recommendations and intervention strategies for promoting physical activity. The discussion is predicated on the belief that physical activity is a complex, dynamic process. During their lives, individuals typically move through various phases of exercise participation that are determined by diverse factors. This chapter discusses physical activity determinants in two broad categories: individual characteristics, including motivations, self-efficacy, exercise history, skills, and other health behaviors; and environmental characteristics such as access, cost, and time barriers and social and cultural supports.

Pricing and promotion effects on low-fat vending snack purchases: the CHIPS Study

OBJECTIVES

This study examined the effects of pricing and promotion strategies on purchases of low-fat snacks from vending machines.

METHODS

Low-fat snacks were added to 55 vending machines in a convenience sample of 12 secondary schools and 12 worksites. Four pricing levels (equal price, 10% reduction, 25% reduction, 50% reduction) and 3 promotional conditions (none, low-fat label, low-fat label plus promotional sign) were crossed in a Latin square design. Sales of low-fat vending snacks were measured continuously for the 12-month intervention.

RESULTS

Price reductions of 10%, 25%, and 50% on low-fat snacks were associated with significant increases in low-fat snack sales; percentages of low-fat snack sales increased by 9%, 39%, and 93%, respectively. Promotional signage was independently but weakly associated with increases in low-fat snack sales. Average profits per machine were not affected by the vending interventions.

CONCLUSIONS

Reducing relative prices on low-fat snacks was effective in promoting lower-fat snack purchases from vending machines in both adult and adolescent populations.

Behavioral science research in diabetes: lifestyle changes related to obesity, eating behavior, and physical activity

Lifestyle factors related to obesity, eating behavior, and physical activity play a major role in the prevention and treatment of type 2 diabetes. In recent years, there has been progress in the development of behavioral strategies to modify these lifestyle behaviors. Further research, however, is clearly needed, because the rates of obesity in our country are escalating, and changing behavior for the long term has proven to be very difficult. This review article, which grew out of a National Institute of Diabetes and Digestive and Kidney Diseases conference on behavioral science research in diabetes, identifies four key topics related to obesity and physical activity that should be given high priority in future research efforts: 1) environmental factors related to obesity, eating, and physical activity; 2) adoption and maintenance of healthful eating, physical activity, and weight; 3) etiology of eating and physical activity; and 4) multiple behavior changes. This review article discusses the significance of each of these four topics, briefly reviews prior research in each area, identifies barriers to progress, and makes specific research recommendations.

Social, educational, and psychological correlates of weight status in adolescents

OBJECTIVES

The purpose of this research was to examine the social, educational, and psychological correlates of weight status in an adolescent population. It was hypothesized that obese adolescents would differ on psychological, social, and educational variables compared with their non-overweight peers.

RESEARCH METHODS AND PROCEDURES

In this cross-sectional study, a population-based sample of 4742 male and 5201 female public school students in the 7th, 9th, and 11th grades responded anonymously to a classroom administered questionnaire. Body mass index was calculated from self-reported height and weight and categorized into four classes of weight status: underweight (<15th percentile), average weight (15th to 85th percentile), overweight (>85th to 95th percentile), and obese (>95th percentile). The questionnaire also included questions about social experiences, psychological well-being, educational experiences, and future goals. Associations of weight status with social, psychological, and educational variables and future goals were explored.

RESULTS

After adjustment for grade level, race, and parental socioeconomic status, obese girls, when compared with their average weight counterparts, were 1.63 (95% confidence interval [CI]: 1.16, 2.30) times less likely to hang out with friends in the last week, 1.49 (95% CI: 1.12, 1.98) times more likely to report serious emotional problems in the last year, 1.79 (95% CI: 1.20, 2.65) times more likely to report hopelessness, and 1.73 (95% CI: 1.21, 1.98) times more likely to report a suicide attempt in the last year. Obese girls were also 1.51 (95% CI: 1.09, 2.10) times more likely to report being held back a grade and 2.09 (95% CI: 1.35, 3.24) times more likely to consider themselves poor students compared with average weight girls. Compared with their average weight counterparts, obese boys were 1.91 (95% CI: 1.43, 2.54) times less likely to hang out with friends in the last week, 1.34 (95% CI: 1.06, 1.70) times more likely to feel that their friends do not care about them, 1.38 (95% CI: 1.08, 1.76) times more likely to report having serious problems in the last year, 1.46 (95% CI: 1.05, 0.03) times more likely to consider themselves poor students, and 2.18 (95% CI: 1.45, 3.30) times more likely to expect to quit school. Compared with average weight boys, underweight boys were 1.67 (95% CI: 1.30, 2.13) times more likely to report hanging out with friends in the last week, 1.22 (95% CI: 1.01, 1.49) times more likely to report disliking school, and 1.40 (95% CI: 1.06, 1.86) times more likely to consider themselves poor students.

DISCUSSION

Associations of weight status with social relationships, school experiences, psychological well-being, and some future aspirations were observed. Among girls, the pattern of observations indicates that obese girls reported more adverse social, educational, and psychological correlates. Obese as well as underweight boys also reported some adverse social and educational correlates. These findings contribute to an understanding of how adolescent experiences vary by weight status and suggest social and psychological risks associated with not meeting weight and body shape ideals embedded in the larger culture.

Reconciling conflicting findings regarding postcessation weight concerns and success in smoking cessation

Correlates of concern about weight gain following smoking cessation and self-efficacy about controlling weight gain were examined in 940 men and 1,166 women who were surveyed on 2 occasions as part of a randomized trial of work-site interventions for smoking cessation. Weight concerns were positively associated with female sex, body weight, dieting for weight control, nicotine addiction, and social encouragement to quit. Bivariate analyses replicated prior findings that elevated weight concerns are associated with a reduced likelihood of quitting smoking, at least in women. Analyses controlling for demographics, nicotine dependence, and social factors replicated prior findings that weight concerns are not negatively related to smoking cessation and that some measures of concern are positively related to cessation. These analyses suggest that conflicting findings found in this literature are due primarily to how weight concerns are defined and whether covariates like nicotine addiction are used in data analyses.

Fast food restaurant use among women in the Pound of Prevention study: dietary, behavioral and demographic correlates

OBJECTIVE

To examine demographic, behavioral and dietary correlates of frequency of fast food restaurant use in a community-based sample of 891 adult women.

DESIGN

A survey was administered at baseline and 3 y later as part of a randomized, prospective intervention trial on weight gain prevention.

SUBJECTS

Women (n = 891) aged 20-45 y who enrolled in the Pound of Prevention study.

MEASUREMENTS

Frequency of fast food restaurant use, dietary intake, demographic and behavioral measures were self-reported. Dietary intake was measured using the 60-item Block Food Frequency Questionnaire. Body weight and height were directly measured.

RESULTS

Twenty-one percent of the sample reported eating > or = 3 fast food meals per week. Frequency of fast food restaurant use was associated with higher total energy intake, higher percentage fat energy, more frequent consumption of hamburgers, French fries and soft drinks, and less frequent consumption of fiber and fruit. Frequency of fast food restaurant use was higher among younger women, those with lower income, non-White ethnicity, greater body weight, lower dietary restraint, fewer low-fat eating behaviors, and greater television viewing. Over 3 y, increases in frequency of fast food restaurant use were associated with increases in body weight, total energy intake, percentage fat intake, intake of hamburgers, French fries and soft drinks, and with decreases in physical activity, dietary restraint and low-fat eating behaviors. Intake of several other foods, including fruits and vegetables, did not differ by frequency of fast food restaurant use.

CONCLUSION

Frequency of fast food restaurant use is associated with higher energy and fat intake and greater body weight, and could be an important risk factor for excess weight gain in the population.

Smokers with multiple behavioral risk factors: how are they different?

OBJECTIVE

The first aim of the present investigation was to examine cross-sectional differences between smokers who engage in additional health risk behaviors (i.e., high-fat diets and low physical activity levels) and those who do not that could affect readiness for smoking cessation treatment and treatment prognosis. The second aim was to examine prospective associations between risk factor status and smoking outcomes (i.e., cessation and quit attempts).

DESIGN

Data were derived from baseline and 1-year follow-up surveys for the SUCCESS project, a randomized trial of worksite smoking interventions conducted in 24 worksites in Minneapolis/St. Paul, Minnesota. Included in the analyses were 2,149 study participants who reported smoking at baseline.

METHODS

Current smokers were categorized into one of three "risk groups": the "1 additional risk factor" group (i.e., either low physical activity level or high dietary fat intake), the "2 additional risk factor" group (i.e., both low physical activity and high dietary fat intake), and the "smoker only" group (i.e., neither low physical activity nor high dietary fat intake). Mixed model regression analyses examined cross-sectional associations between risk group status and baseline demographic variables, smoking dependency, social environments for smoking, and health problems. Prospective associations between baseline risk group status and 1-year follow-up cessation attempts and quits were also examined.

RESULTS

At baseline, risk factor status was associated with smoking dependency for both men and women. Women smokers with at least one additional risk factor reported a greater number of cigarettes smoked per day, higher Fagerstrom Nicotine Dependence scores, and lower self-efficacy for refraining from smoking in a variety of situations compared with smokers with no additional risk factors. Men smokers with at least one additional risk factor reported higher Fagerstrom Nicotine Dependence scores compared with smokers with no additional risk factors. Women smokers with at least one additional risk factor were more likely to report being encouraged to quit by co-workers compared with smokers with no other risk factors. No relationship between risk factor status and social pressure to quit was observed among men. Prospective analyses indicated that baseline risk factor status was marginally related to smoking outcome at 1-year follow-up; however, these relationships were attenuated considerably when controlling for smoking dependence. Relationships between risk factor status and smoking outcomes were stronger for men.

CONCLUSION

Results indicated that the presence of multiple health risk behaviors was related to more serious problems with smoking. However, the presence of additional risk factors did not strongly affect prognosis for smoking cessation.

Can anyone successfully control their weight? Findings of a three year community-based study of men and women

This study examined the prevalence, distribution and correlates of successful weight loss and successful weight maintenance over three years in a community-based sample of 854 subjects aged 20-45 at baseline. More than half (53.7%) of the participants in the study gained weight within the first twelve months, only one in four (24.5%) successfully avoided weight gain over three years, and less than one in twenty (4.6%) lost and maintained weight successfully. The findings underscore the importance of current public health efforts to prevent weight gain, and suggest that without much greater efforts to promote and support weight control the prevalence of obesity will continue to rise.

Temporal trends in energy intake in the United States: an ecologic perspective

BACKGROUND

The causes of recent increases in the prevalence of overweight in the United States are perplexing because national survey data do not show clear patterns of change in energy intake or expenditure.

OBJECTIVE

Ecologic data regarding the quantities and types of foods and nutrients available in the United States between 1970 and 1998 were reviewed to provide an alternative perspective on trends in energy intake.

DESIGN

Literature searches in agriculture, business, and medical library databases were conducted to identify data regarding the quantities and types of foods and nutrients available in the United States between 1970 and 1998.

RESULTS

Per capita energy availability estimates from the US Department of Agriculture, US Food Supply Series, indicate that energy availability increased by 15% between 1970 and 1994. Data regarding trends in food purchasing and preparation suggest that Americans are eating more meals outside the home, relying more heavily on convenience foods, and consuming larger food portions. Americans appear, in some cases, to be selecting lower-fat foods over higher-fat alternatives. In addition, availability and sales of reduced-energy and reduced-fat products have increased.

CONCLUSION

Consistent with trends in overweight, most of the ecologic data reviewed suggest that energy intake has increased over the past several decades and is likely a major contributor to increases in average body weight.

Reconciling conflicting findings regarding postcessation weight concerns and success in smoking cessation

Correlates of concern about weight gain following smoking cessation and self-efficacy about controlling weight gain were examined in 940 men and 1,166 women who were surveyed on 2 occasions as part of a randomized trial of work-site interventions for smoking cessation. Weight concerns were positively associated with female sex, body weight, dieting for weight control, nicotine addiction, and social encouragement to quit. Bivariate analyses replicated prior findings that elevated weight concerns are associated with a reduced likelihood of quitting smoking, at least in women. Analyses controlling for demographics, nicotine dependence, and social factors replicated prior findings that weight concerns are not negatively related to smoking cessation and that some measures of concern are positively related to cessation. These analyses suggest that conflicting findings found in this literature are due primarily to how weight concerns are defined and whether covariates like nicotine addiction are used in data analyses.

Predictors of weight gain in the Pound of Prevention study

OBJECTIVES

This study examined cross-sectional and prospective relationships between macronutrient intake, behaviors intended to limit fat intake, physical activity and body weight.

DESIGN

The overall goal was to identify diet and exercise behaviors that predict and/or accompany weight gain or loss over time. Specific questions addressed included: (a) are habitual levels of diet or exercise predictive of weight change; (b) are habitual diet and exercise levels associated cross-sectionally with body weight; and (c) are changes in diet and exercise associated with changes in body weight over time?

PARTICIPANTS

Subjects were a sample of community volunteers (n=826 women, n=218 men) taking part in a weight gain prevention project over a 3-year period.

MEASURES

Body weight was measured at baseline and annually over the study period. Self-report measures of diet and exercise behavior were also measured annually.

RESULTS

Among both men and women, the most consistent results were the positive association between dietary fat intake and weight gain and an inverse association between frequency of physical activity and weight gain. Individuals who weighed more both ate more and exercised less than those who weighed less. Individuals who increased their physical activity level and decreased their food intake over time were protected from weight gain compared to those who did not. Frequency of high-intensity physical activity was particularly important for both men and women. Additionally, women who consistently engaged in higher levels of moderate physical activity gained weight at a slower rate compared to women who were less active.

CONCLUSIONS

Overall results indicated that both cross-sectionally and prospectively, the determinants of weight and weight change are multifactorial. Attention to exercise, fat intake and total energy intake all appear important for successful long term control of body weight.

Public health interventions for the prevention and treatment of obesity

Epidemic obesity is one of the few undesirable consequences of humanity's mastery of the environment. This article reviews public health approaches to preventing and treating obesity. The most encouraging efforts to date have been interventions targeting children in both medical and community surroundings. Treating and preventing obesity in adults has been less successful. It is suggested that taking an environmental health perspective on the obesity problem may facilitate the advancement of scientific understanding of this important health issue.

Associations between exercise and health behaviors in a community sample of working adults

BACKGROUND

The present study examined the associations between leisure-time exercise and a range of health behaviors and reports of illness and injury in a sample of community working adults.

METHODS

The study population included 4907 women and 4136 men who completed surveys in 24 worksites in the Minneapolis-St. Paul metropolitan area.

RESULTS

Participants in the study were ranked by gender according to their exercise score and grouped into quartiles. Women and men in the highest activity quartiles were more highly educated and were younger. High-activity men were more likely to be unmarried. Higher levels of leisure-time exercise were positively associated with seat belt use and inversely related to smoking, dietary fat intake, reported stress, and obesity. In men only, leisure-time exercise was related to greater reports of injuries resulting in restriction of usual activities. In women only, leisure-time exercise was positively associated with daily alcohol use. Most of the significant associations were seen in the two highest quartiles of exercise.

CONCLUSIONS

These findings suggest that associations between leisure-time exercise and health behaviors occur at the higher levels of exercise and interventions may need to promote this higher level of leisure-time exercise to impact overall public health.

Long-term maintenance of weight loss: current status

Intervention strategies for promoting long-term weight loss are examined empirically and conceptually. Weight control research over the last 20 years has dramatically improved short-term treatment efficacy but has been less successful in improving long-term success. Interventions in preadolescent children show greater long-term efficacy than in adults. Extending treatment length and putting more emphasis on energy expenditure have modestly improved long-term weight loss in adults. Fresh ideas are needed to push the field forward. Suggested research priorities are patient retention, natural history, assessment of intake and expenditure, obesity phenotypes, adolescence at a critical period, behavioral preference-reinforcement value, physical activity and social support, better linkage of new conceptual models to behavioral treatments, and the interface between pharmacological and behavioral methods.

Stage of change as a predictor of success in weight control in adult women

Weight change over 3 years was examined in a large and heterogeneous sample of women as a function of stage of change for weight control. Women were classified into Precontemplation, Contemplation, Preparation, and Action stages on the basis of reports of current and past weight control behaviors and future intentions. Stage of change did not predict success in weight control. Mean weight changes over 3 years were 1.1 kg, 1.0 kg, 2.1 kg, and 2.3 kg for Precontemplation, Contemplation, Preparation, and Action stages, respectively. The findings call into question the generality of the stages-of-change classification system across behavioral domains.

Age of initiation, smoking patterns, and risk in a population of working adults

BACKGROUND

Early age of initiation is a significant risk factor for long-term dependent smoking and may also relate to other unhealthy behaviors and increased likelihood of illness, independent of duration of smoking.

METHODS

The current study assessed age of initiation in relation to cigarette dependence, interest in quitting, social environment pertaining to smoking, behavioral risk factors, and current health problems. Subjects were 2120 current daily smokers in 24 worksites in the Minneapolis/St. Paul, Minnesota, metropolitan area.

RESULTS

Findings were surprisingly consistent with early age of initiation predicting more dependent smoking, less interest and confidence in ability to quit, poorer diet, less use of seat belts, more illness and hospitalization, and greater likelihood of smoking among partner/spouse, friends, and co-workers.

CONCLUSIONS

The overall strength of the findings was unexpected. Early initiation of regular smoking predicted a significant constellation of risk factors throughout adulthood. Interventions that significantly delay smoking onset, even in the absence of permanent prevention, could have important public health implications.

Mistreatment due to weight: prevalence and sources of perceived mistreatment in women and men

OBJECTIVE

Previous research has documented prejudicial attitudes and discrimination against overweight people. Yet the extent to which overweight people themselves perceive that they have been mistreated because of their weight has not been carefully studied. The purpose of this study was to examine the prevalence of perceived mistreatment due to weight and sources of perceived mistreatment.

METHODS AND PROCEDURES

A non-clinical sample of healthy adults (187 men and 800 women) enrolled in a weight gain prevention program comprised the study population. A self-administered questionnaire was used to measure perceived mistreatment due to weight.

RESULTS

Overall, 22% of women and 17% of men reported weight-related mistreatment. The most commonly reported sources of mistreatment among women were strangers (12.5%) and a spouse or loved one (11.9%). Men were most likely to report mistreatment by a spouse or loved one (10.2%) and friends (7.5%). Somewhat surprisingly, sex differences in perceived weight-related mistreatment were significant only for stranger as the source. Perceived weight-related mistreatment was positively associated with body mass index (BMI) (r = 0.39, p<0.0001). Reported mistreatment was nearly ten times as pervalent among individuals in the highest quartile of the BMI distribution (42.5%) than among those in the lowest BMI quartile (5.7%), but was significantly greater than zero in all but the very lean.

DISCUSSION

Perceived mistreatment due to weight is a common experience and is not restricted to the morbidly obese. Results are discussed in light of the sociocultural value for thinness.

Stage of change as a predictor of success in weight control in adult women

Weight change over 3 years was examined in a large and heterogeneous sample of women as a function of stage of change for weight control. Women were classified into Precontemplation, Contemplation, Preparation, and Action stages on the basis of reports of current and past weight control behaviors and future intentions. Stage of change did not predict success in weight control. Mean weight changes over 3 years were 1.1 kg, 1.0 kg, 2.1 kg, and 2.3 kg for Precontemplation, Contemplation, Preparation, and Action stages, respectively. The findings call into question the generality of the stages-of-change classification system across behavioral domains.

Confidence of health professionals in public health approaches to obesity prevention

OBJECTIVE

To assess the views of professionals working in the obesity field on the potential usefulness and feasibility of implementing different types of public health prevention strategies.

METHOD

A questionnaire listing 20 public health strategies was mailed to pre-registrants of an international obesity prevention symposium. Respondents were asked to rate how useful and how feasible they felt each of the listed actions would be for the prevention of obesity in their home countries. The list included education-based strategies aimed at changing individual behaviour as well as more radical measures aimed at reducing population exposure to obesity-promoting factors in the environment.

RESULTS

A 32% response was obtained. Education-based strategies were seen to be both useful and feasible. Less confidence was expressed in strategies aimed at changing the environment.

CONCLUSION

People working in the obesity field tend to feel most comfortable with education-based prevention strategies. Implementation of environment-based strategies needed to encourage and support behaviour change may require the involvement of people from relevant sectors outside the obesity field.

Intraclass correlation for measures from a worksite health promotion study: estimates, correlates, and applications

Intervention trials that employ a group-randomized trial design require an adaptation of the usual analytic methods to account for the randomization of intact economic/social groups to study conditions and the positive ICC that is implied by such a design. In the absence of valid estimates of the ICCs for the outcomes of interest, investigators designing trials could only guess at how large a problem they faced and how much they would need to increase sample size to compensate. Aside from this paper, we are aware of only one other publication that provides such estimates, and that study provides estimates for only a handful of outcomes. Our purpose here has been to provide a replication and extension of those findings to a broader array of outcomes. The results presented here suggest that worksite-level ICCs for a variety of smoking and health-related outcomes are generally small and that these ICCs can generally be reduced by adjustment for individual-level characteristics. We have demonstrated how information about these ICCs can be incorporated in sample size calculations to avoid designing "underpowered" studies. Our results should assist investigators in planning studies to evaluate the effectiveness of worksite-based health promotion efforts.

Prevalence and correlates of binge eating in a nonclinical sample of women enrolled in a weight gain prevention program

OBJECTIVES

The aims of the present study were to examine the prevalence and correlates of binge eating in a nonclinical sample of women and to examine whether associations differed by overweight status.

DESIGN

Cross-sectional comparison of women based on self-reported binge eating status (large amount of food eaten and feelings of lack of control during these eating episodes) and overweight status (measured body weight: overweight defined as body mass index (BMI) > or = 27.3 kg/m2).

PARTICIPANTS

Subjects were 817 women aged 20-45y from the community who enrolled in a three year prospective intervention study to examine methods for preventing age-related weight gain.

MEASURES

Body weight was measured at baseline and three-year follow-up. Self-report measures of binge eating, dieting practices, eating and exercise behaviours, depression, self-esteem and stressful life events were collected at the three-year follow-up.

RESULTS

The prevalence of binge eating in the past six months was 9% among normal weight women and 21% among overweight women. The frequency of binge eating was low (> 50% of binge eaters binged less than once per week) and did not significantly differ by body weight status. Compared to non-binge eaters, binge eaters reported more dieting practices, more extreme attitudes about weight and shape, and higher levels of depression and stressful life events. Binge eating was not related to habitual eating and exercise behaviours. In multivariate models, weight/shape importance (odds ratio (OR) = 3.33; 95% confidence intervals (95% CI) = 2.10, 5.29), depression (OR = 1.73; 95% CI = 1.07, 2.79) and history of intentional weight loss episodes (OR = 1.68; 95% CI = 1.03, 1.13) were independently associated with increased odds of binge eating.

CONCLUSIONS

Binge eating is about twice as prevalent among overweight women, compared to normal weight women, in a nonclinical sample, but has similar correlates (that is, dieting, depression, weight/shape preoccupation). Prospective research is needed to determine whether there are causal associations between binge eating, depression, dieting and weight gain.

Preventing weight gain in adults: the pound of prevention study

OBJECTIVES

This study examined whether weight gain with age could be prevented through the use of a low-intensity intervention.

METHODS

Participants, 228 men and 998 women recruited from diverse sources, were randomized to one of the following groups: (1) no-contact control, (2) education through monthly newsletters, or (3) education plus incentives for participation. All participants were weighed and completed questionnaires about behaviors and attitudes related to weight at baseline and annually for 3 years thereafter.

RESULTS

Individuals in intervention groups reported favorable changes over time in frequency of weighting and healthy dieting practices relative to those in the control group. These behavior changes were in turn related to a reduced rate of weight gain over time. However, weight gain over 3 years did not differ significantly by treatment group.

CONCLUSIONS

This low-intensity educational approach to weight gain prevention sustained interest over a lengthy time period and was associated positively with behavior change, but it was not strong enough to significantly reduce weight gain with age.

Binge status as a predictor of weight loss treatment outcome

OBJECTIVE

A widely held clinical belief is that individuals with binge eating problems fare poorly in weight loss programs. The empirical evidence regarding the prognostic significance of binge eating, however, is mixed. The goals of this study were to examine psychological and behavioral characteristics associated with binge eating and the prognostic significance of binge eating for short- and long-term weight loss in a large sample of women treated for obesity.

DESIGN

The dataset used in the current study was a combined sample of women (n = 444) who participated in one of three behavioral weight loss research studies.

MATERIALS AND METHOD

Measures of dieting and weight history were obtained at baseline. Body weight, the Binge Eating Scale (BES), a measure of perceived barriers to weight loss, the Beck Depression Inventory, the Block Food Frequency Questionnaire, and the Paffenbarger Physical Activity Questionnaire were assessed at baseline, 6 months and 18 months. Regression analyses examined cross-sectional associations between the BES and the other variables at baseline, prospective associations between baseline BES and changes in weight and the psychological and behavioral variables over time, and temporal covariations between BES and the other variables over time.

RESULTS

Cross-sectional analyses showed baseline binge eating status to be strongly associated with dieting history, weight cycling, depressive symptomatology and perceived barriers to weight loss. Women with binge eating problems were also more likely to drop out of treatment. Baseline binge status was not associated with 6-month weight loss, but was weakly predictive of less weight loss success at 18 months. Binge status at baseline did not predict changes in dietary intake, physical activity, perceived barriers to weight loss or depressive symptomatology at either 6 months or 18 months. In time-dependent covariance analyses, changes in BES scores were significantly associated with changes in body weight, independent of changes in dietary intake and physical activity. However, when depression scores are included in the analysis, the association between binge score and body weight was no longer statistically significant.

CONCLUSION

These findings suggest that baseline binge status was a weak prognostic indicator of success in women who are moderately obese and are seeking treatment for weight loss. Although assessments of binge status covary with weight loss and regain, the relationship appears to be mediated by psychological dysphoria.

Television viewing, physical inactivity and obesity

This study examined the relationship between TV viewing and three year change in BMI among a community-based sample of 176 men, 428 high-income women and 277 low-income women who were aged 20-45 years at baseline. Cross-sectionally, TV viewing was positively associated with BMI among women, but not among men. This relationship was strongest among low-income women, with only a marginal relationship among high-income women. There were no significant relationships between change in BMI and number of hours of TV viewing at baseline, average number of hours of TV viewing over the three year follow-up, or change in number of hours of TV viewing from baseline to three years. These findings suggest the link between obesity and TV viewing is complex, and that TV viewing may not be the simple marker of sedentariness we may have hoped.

Prospective study of intentionality of weight loss and mortality in older women: the Iowa Women's Health Study

Several epidemiologic investigations have suggested that weight loss is associated with increased mortality risk but have not examined whether the weight loss was intentional or unintentional. The authors examined whether the association between weight loss and mortality differs by whether the weight loss was intentional or unintentional as part of the Iowa Women's Health Study, a prospective cohort study of health risk factors in postmenopausal women. Women aged 55-69 years completed questions about intentional and unintentional weight losses since age 18 years via mail survey in 1992 and were followed through 1995. One or more intentional weight loss episodes of 20 or more pounds (> or =9.1 kg) during adulthood was not significantly associated with higher total or cardiovascular disease mortality risk compared with never losing > or =20 pounds. One or more unintentional weight loss episodes of 20 or more pounds was associated with a 26-57% higher total mortality risk and a 51-114% higher cardiovascular disease mortality risk, compared with never losing 20 or more pounds. Associations between unintentional weight loss and increased mortality risk were confined mostly to women with prevalent disease, hypertension, or diabetes. Patterns of association did not vary by overweight status. These findings suggest that the association between weight loss and increased mortality risk observed in epidemiologic studies may be due to unintentional weight loss that reflects existing disease and not due to intentional weight loss.

Use of personal trainers and financial incentives to increase exercise in a behavioral weight-loss program

Exercise is the best predictor of long-term weight loss. This study evaluated two strategies for improving exercise adherence and long-term weight loss in obese outpatients. Obese men and women (N = 193) were randomized to 1 of 5 treatment groups for 18 months: standard behavior therapy (SBT); SBT with supervised walks (SW) 3 times per week; SBT + SW with personal trainers (PT), who walked with participants, made phone reminders, and did make-up SW; SBT + SW with monetary incentives (I) for completing SW; and SBT + SW + PT + I. Both PT and I enhanced attendance at SWs, the combination producing the best adherence. Increased walk attendance did not result in higher overall energy expenditure, however, and long-term weight loss was also not improved. Post hoc analyses suggest that the level of exercise needed for successful long-term weight loss is much higher than that usually recommended in behavioral treatment programs.

Is dieting good for you?: Prevalence, duration and associated weight and behaviour changes for specific weight loss strategies over four years in US adults

OBJECTIVES

This present study describes weight control strategies used by a heterogeneous sample of US adults and their associations with weight and behaviour change over time.

DESIGN

A prospective cohort study.

PARTICIPANTS

Participants for this study were 1120 US adults recruited from the community who enrolled in a three-year intervention study to examine methods for preventing age-related weight gain.

MEASURES

Measured body weight and self-reported behaviours related to body weight (dieting practices, dietary intake and physical activity) were completed annually for four years.

RESULTS

Over 70% reported using each of the following dieting strategies at least once in four years: increase exercise (82.2%); decrease fat intake (78.7%); reduce food amount (78.2%); and reduce calories (73.2%). Cumulative duration of use of these behaviours was brief (for example, even the most common behaviours were used only 20% of the time). Global reports of dieting were not predictive of weight change over time. However, a dose-response relationship was observed between reported duration of use of several specific weight loss strategies over the four years and change in behaviours and weight gain.

CONCLUSIONS

These findings suggest that public health recommendations for weight control may need to place greater emphasis on persistence of weight control behaviours.

Weight control behaviors among adult men and women: cause for concern?

OBJECTIVES

To examine gender differences in weight control behaviors; their duration and the consistency of their use over a 3-year period; and variations of these behaviors by body mass index (BMI).

RESEARCH METHODS AND PROCEDURES

The study population included 714 women and 229 men participating in a community-based weight gain prevention program who completed surveys about their weight control behaviors annually for 3 years. General dieting behaviors (e.g., current, regular, and past dieting), dietary restraint (using Restrained Eating subscale of the Three-Factor Eating Questionnaire), and specific weight control practices (e.g., increasing exercise, skipping meals, and taking laxatives) were assessed.

RESULTS

Women were more likely than men to report weight control behaviors, with particularly strong associations found between gender and "history of dieting" (odds ratio = 8.1) and "participation in an organized weight loss program" (odds ratio = 11.7). Among both genders, exercise was the most frequently reported specific weight loss practice (66% of women and 53% of men), followed by decreasing fat intake (62% of women and 48% of men). The use of at least one unhealthy weight control behavior over the past year was reported by 22% of the women and 17% of the men. Gender differences were not found for duration of use of most of the specific weight control practices over the past year, or for consistency of general dieting behaviors and dietary restraint over time. Although both gender and BMI were strongly associated with dieting behaviors, interactions between gender and BMI on prevalence rates of dieting were not significant.

DISCUSSION

Although weight control behaviors were more prevalent among women than men, in general, large gender differences were not found in the types of behaviors used and the duration and consistency of their use. The high percentages of adults using healthy methods of weight control was encouraging. However, there is still cause for concern, in that unhealthy weight control practices were also reported by a significant percentage of the population.

Benefits of recruiting participants with friends and increasing social support for weight loss and maintenance

To determine the benefits of social support for weight loss and maintenance, this study recruited participants (N = 166) either alone or with 3 friends or family members and then randomly assigned them to a standard behavioral treatment (SBT) or SBT with social support strategies. Participants recruited with friends had greater weight losses at the end of the 4-month treatment and at Month 10 follow-up. Both recruitment strategy and the social support manipulation affected treatment completion and weight-loss maintenance. In those recruited alone and given SBT, 76% completed treatment and 24% maintained their weight loss in full from Months 4 to 10. Among those recruited with friends and given SBT plus social support, 95% completed treatment and 66% maintained their weight loss in full.