Mediators of Weight Loss Maintenance in the Keep It Off Trial.

Background: An important step toward enhancing the efficacy of weight loss maintenance interventions is identifying the pathways through which successful interventions such as the Keep It Off trial have worked. Purpose: This study aimed to assess the viability of mediated relationships between the Keep It Off Guided intervention, conceptually and empirically grounded potential mediators, and weight. Repeated measurement of mediators and weight enabled documentation of the temporal ordering of intervention delivery and changes in mediators and in weight among participants randomized to the Guided intervention or Self-Directed comparison group. Methods: Total, direct, and indirect effects of the Guided intervention on weight change were calculated and tested for significance. Indirect effects were comprised of the influence of the intervention on three change scores for each mediator and the relationship between mediator changes and weight changes 6 months later. Results: Guided intervention participants regained about 2% less weight over 24 months than Self-Directed participants. Starting daily self-weighing accounted for the largest share of this difference, followed by not stopping self-weighing. Conclusions: Daily self-weighing mediated 24-month weight loss maintenance. Trial Registration Number: The trial is registered with ClinicalTrials.gov (Identifier: NCT00702455 www.clinicaltrials.gov/ct2/show/NCT00702455).

Resilience to obesity among socioeconomically disadvantaged women: the READI study.

OBJECTIVE: This cross-sectional study aimed to identify sociodemographic and behavioural characteristics of 'overweight-resilient' women, that is, women who were in a healthy body weight range, despite living in socioeconomically disadvantaged neighbourhoods that place them at increased risk of obesity. The study also aimed to test a comprehensive theoretically derived model of the associations between intrapersonal, social and environmental factors and obesity among this target group. PARTICIPANTS: A total of 3235 women aged 18-45 years from 80 urban and rural neighbourhoods throughout Victoria, Australia, participated in the Resilience for Eating and Activity Despite Inequality study. MEASUREMENTS: Women reported height, weight, sociodemographic characteristics, leisure-time physical activity, dietary behaviours and a range of theoretically derived cognitive, social and neighbourhood environmental characteristics hypothesized to influence obesity risk. A theoretical model predicting body mass index (BMI) was tested using structural equation models. RESULTS: Women classified as 'resilient' to obesity tended to be younger, born overseas, more highly educated, unmarried and to have higher or undisclosed household incomes. They engaged in more leisure-time physical activity and consumed less fast foods and soft drinks than overweight/obese women. Neighbourhood characteristics, social characteristics and cognitive characteristics all contributed to explaining variation in BMI in the hypothesized directions. CONCLUSIONS: These results demonstrate several characteristics of women appearing 'resilient' to obesity, despite their increased risk conferred by residing in socioeconomically disadvantaged neighbourhoods. Acknowledging the cross-sectional study design, the results advance theoretical frameworks aimed at investigating obesity risk by providing evidence in support of a comprehensive model of direct and indirect effects on obesity of neighbourhood, as well as social, cognitive and behavioural characteristics.

Changes in C-reactive protein during weight loss and the association with changes in anthropometric variables in men and women: LIFE Study.

OBJECTIVE: To investigate whether sex differences exist in the pattern of change in C-reactive protein (CRP) levels during weight loss, and whether the associations between weight change and CRP change differ by the types of anthropometric variables. DESIGN: Longitudinal, prospective analysis of subjects participating in an intentional weight loss trial (the Lose It For Ever: LIFE Study) followed-up for 30 months. SUBJECTS: A total of 212 healthy, obese men and women (age: 23-77 years, body mass index (BMI): 30-39 kg m(-2)) took part in this study. MEASUREMENTS: BMI, waist and hip circumferences, and waist-to-hip ratio, CRP and lifestyle variables repeatedly measured at baseline, 6, 12, 18 and 30-month follow-up. RESULTS: Weight change was J shaped with a nadir at 12 months in both men and women (P for month(2) <0.0001). CRP level was consistently higher in women than in men, but the differences were less prominent and were not statistically significant at 12- and 18-month follow-up. CRP changes between any two consecutive visits were significantly associated with changes in BMI during the same period in women. However, the associations between CRP changes and changes in waist or hip circumference were not as consistent, especially between 18- and 30-month follow-up when CRP significantly increased. The associations in men were generally similar among the different anthropometric measures. The association between changes in BMI and CRP was stronger in men than in women. CONCLUSION: BMI change generally correlated well with CRP changes in both men and women in the course of follow-up. Significant sex difference in CRP level at baseline diminished at 12- and 18-month follow-up, when both sexes had maintained the lost weight.

Are standard behavioral weight loss programs effective for young adults?

OBJECTIVE: To compare the enrollment, attendance, retention and weight losses of young adults in behavioral weight loss (BWL) programs with older participants in the same trials. METHODS: Data were pooled from three NIH-funded adult BWL trials from two clinical centers in different regions of the country (total N=298); young adults were defined as those aged 18-35 years. Both young adults and adults were compared on session attendance, retention at the 6-month assessment, weight loss and physical activity at 6 months. RESULTS: Young adults represented 7% of the sample, attended significantly fewer sessions than did adults (52 vs 74%, respectively; P<0.001) and were less likely to be retained for the 6-month assessment (67 vs 95%, respectively; P<0.05). Controlling for demographic variables, study and baseline weight, the mean weight losses achieved were significantly less for young adults compared with adults (-4.3 kg (6.3) vs -7.7 kg (7.0), respectively; P<0.05); fewer young adults achieved > or =5% weight loss at 6 months compared with older participants (8/21 (38%) vs 171/277 (62%); P<0.05). After controlling for session attendance, differences in the mean weight loss were not significant (P=0.81). Controlling for baseline values, study and demographics, changes in total physical activity over the initial 6 months of treatment were less for young adults compared with adults, but these differences only approached statistical significance (P=0.07). CONCLUSION: These data indicate that standard programs do not meet the weight control needs of young adults. Research is urgently required to improve recruitment and retention efforts with this high-risk group.

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.

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.

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.

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

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.

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.

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.