Predictors of weight loss success. Exercise vs. dietary self-efficacy and treatment attendance

False and true pre-treatment predictors of weight loss in obese patients starting a program for lifestyle change

PURPOSE

Weight loss treatment effectiveness and cost-effectiveness may be improved by the identification of patients who are more prone to participate and gain benefit from specific interventions. Aim of the present study is to identify easily available additional predictors of weight loss among data usually present in the medical records of obese/overweight patients attending an outpatient clinic for a non-pharmacological lifestyle change program.

RESULTS

268 patients, 74 men and 195 women (age 43.2 ± 11.9 years, BMI 38.9 ± 6.8 kg/m(2)) were enrolled. Among these patients, only 35.6 % men and 22.7 % women completed the 6-month protocol. Among participants, 50.7 % lost at least 5 % initial body weight after 6 months (SUCCESSES), while 49.3 % failed (FAILURES). Baseline nutritional parameters (total Kcal, lipid, carbohydrate, protein and alcohol intake) were not significantly different in successes when compared to failures, while a significant difference between groups was observed for baseline diastolic blood pressure (DBP); free fat mass (FFM); muscle mass (MM); total body water (TBW); HDL cholesterol; ALT; AST; γGT. After dividing into quartiles the not-normally distributed variables, successes had AST values above median (3rd and 4th quartiles; χ (2) = 0.003). At multivariate analysis (linear regression), the OR was 3.34 (1.42-7.85; p = 0.006).

CONCLUSIONS

In our patients, baseline liver enzyme levels (AST in particular), but not baseline quantitative and qualitative dietary intake, were significantly different in successes versus failures and could therefore represent a predictor of success. In conclusion, AST could represent a usually available biomarker that could be used as a predictor of outcome (weight loss) in obese patients starting a lifestyle change program.

Effect of glycemic load on eating behavior self-efficacy during weight loss

High eating behavior self-efficacy may contribute to successful weight loss. Diet interventions that maximize eating behavior self-efficacy may therefore improve weight loss outcomes. However, data on the effect of diet composition on eating behavior self-efficacy are sparse. To determine the effects of dietary glycemic load (GL) on eating behavior self-efficacy during weight loss, body weight and eating behavior self-efficacy were measured every six months in overweight adults participating in a 12-mo randomized trial testing energy-restricted diets differing in GL. All food was provided during the first six months and self-selected thereafter. Total mean weight loss did not differ between groups, and GL-level had no significant effect on eating behavior self-efficacy. In the combined cohort, individuals losing the most weight reported improvements in eating behavior self-efficacy, whereas those achieving less weight loss reported decrements in eating behavior self-efficacy. Decrements in eating behavior self-efficacy were associated with subsequent weight regain when diets were self-selected. While GL does not appear to influence eating behavior self-efficacy, lesser amounts of weight loss on provided-food energy restricted diets may deter successful maintenance of weight loss by attenuating improvements in eating behavior self-efficacy.

Personnel and participant experiences of a residential weight-loss program. A qualitative study

Background

Residential weight-loss programs aim to help persons with obesity lose weight and maintain a long-term healthy lifestyle. Knowledge is needed on the different actors’ perceptions and experiences from such programs. The aim of this study was to describe how personnel argued for and perceived a residential weight-loss program, to investigate how the participants experienced the program, and to contrast these perspectives.

Methods

This qualitative study took place in an 18-week residential weight-loss program. Exercise, diet, and personal development were the main components in the program. Data was collected through participant observation and individual and focus group interviews with participants and personnel.

Results

Program personnel characterized persons with obesity in specific terms, and these formed the basis of the educational aims, teaching principles, and content of the program. According to personnel, persons with obesity typically had problems acknowledging their own resources, lived unstructured lives, had a distorted relationship to food, experienced a range of social problems and featured a lack of personal insight. Program participants reported enthusiasm about their experiences of exercise and appreciated measures of success with the exercise program. They had, however, very different experiences regarding the usefulness and appropriateness of the parts of the program focused on social and personal development. Some felt that weight loss required an engagement with personal development while others viewed it as unnecessary and inappropriate.

Conclusion

The reliance in personnel accounts on particular characteristics of persons with obesity as a rationale for the program might lead to stigmatizing and stereotyping. Program activities focused on social and personal development need to be better understood by participants if they are to be viewed as helpful. To achieve this personnel must carefully consider how these parts of the program are communicated and conducted.

Self-efficacy for temptations is a better predictor of weight loss than motivation and global self-efficacy: evidence from two prospective studies among overweight/obese women at high risk of breast cancer

OBJECTIVES

Identifying predictors of weight loss could help to triage people who will benefit most from programs and identify those who require additional support. The present research was designed to address statistical, conceptual and operational difficulties associated with the role of self-efficacy in predicting weight loss.

METHODS

In Study 1, 115 dieting overweight/obese women at high risk of breast cancer were weighed and completed questionnaires assessing motivation, global self-efficacy and self-efficacy for temptations. The main outcome measure was weight, measured 3-months post-baseline. Study 2 was identical (n=107), except changes in psychological variables were computed, and used to predict weight 6-months post-baseline.

RESULTS

In Study 1, self-efficacy for temptations was a significant predictor of weight loss at 3-month follow-up. In Study 2, improved self-efficacy for temptations between baseline and four-weeks was predictive of lower weight at 6 months.

CONCLUSION

The key finding was that self-efficacy for temptations, as opposed to motivation and global self-efficacy, was predictive of subsequent weight loss.

PRACTICE IMPLICATIONS

The implication is that augmenting dieters' capability for dealing with temptations might boost the impact of weight loss programs.

Preliminary efficacy of prize-based contingency management to increase activity levels in healthy adults

An estimated 30% of Americans meet the criteria for obesity. Effective, low-cost interventions to increase physical activity are needed to prevent and treat obesity. In this study, 11 healthy adults wore Fitbit accelerometers for 3 weeks. During the initial baseline, subjects earned prize draws for wearing the Fitbit. During intervention, percentile schedules were used to calculate individual prize-draw criteria. The final week was a return to baseline. Four subjects increased step counts as a result of the intervention. A bout analysis of interresponse times revealed that subjects increased overall step counts by increasing daily minutes active and within-bout response rates and decreasing pauses between bouts of activity. Strategies to improve effectiveness are suggested, such as modification of reinforcement probability and amount and identification of the function of periods of inactivity.

Assessing self-efficacy and self-help methods in women with and without Polycystic Ovary Syndrome

Polycystic Ovary Syndrome (PCOS) is a common endocrine disorder in women strongly associated with obesity and psychological dysfunction. It is crucial to assess the contributions of psychological parameters to obesity and weight management. This survey based cross-sectional study assessed self-efficacy, health attitudes and beliefs, response to illness and adult health history in women with (n = 74) and without PCOS (n = 90). There were no significant differences in self-efficacy, health attitudes and beliefs between groups. Women with PCOS reported less engagement in self-help methods compared to women without (p = 0.003). Women with PCOS reported poorer overall (p < 0.001) and recent health history (p = 0.02), greater prevalence (p < 0.001) and impact of a chronic illness (p < 0.001). It is crucial that women recognize that PCOS is a chronic condition requiring on-going lifestyle management; to encourage active engagement in their management, enhance participation in screening for complications and uptake of lifestyle recommendations.

Eating behaviors as predictors of weight loss in a 6 month weight loss intervention

OBJECTIVE

To examine associations between eating behavior constructs and weight loss (WL) in a 6-month WL intervention in worksites.

DESIGN AND METHODS

A cluster-randomized controlled trial of a group behavioral WL intervention versus wait-listed control was conducted at four worksites. Measures included body weight and the eating behavior constructs restraint, disinhibition, hunger, and their sub-constructs. Rates of intervention meeting attendance and weight self-monitoring were also quantified.

RESULTS

WL was greater in intervention participants than controls (ΔI = -8.1±6.8 kg, ΔC = +0.9±3.6 kg, P<0.001). Between-group analyses showed that the intervention was associated with increased restraint (ΔI = 5.43±4.25, ΔC = 0.29±3.80, P<0.001), decreased disinhibition (ΔI = -2.5±3.63, ΔC = 0.66±1.85, P < 0.001) and decreased hunger (ΔI = -2.79±3.13, ΔC = 0.56±2.63, P < 0.001), and changes in all eating behavior subscales. Greater WL in intervention participants was correlated with higher baseline hunger (r = -0.25, P = 0.03), increased restraint (r = -0.35, P=0.001), decreased disinhibition (r = 0.26, P = 0.02), and decreased hunger (r = 0.36, P = 0.001). However, in a multiple regression model including rates of meeting attendance and self-monitoring, decreased hunger was the only eating behavior change that predicted weight loss (R(2) =0.57, P<0.001).

CONCLUSION

Decreased hunger was the strongest predictor of WL in this intervention with relatively high mean WL. Further studies are needed to confirm the central role of hunger management in successful WL.

Biomarker Profile Does Not Predict Weight Loss Success in Successful and Unsuccessful Diet-Reduced Obese Individuals: a Prospective Study

Background. Individuals attempting weight reduction have varying success when participating in the same intervention. Identifying physiological factors associated with greater weight loss could improve outcomes. Methods. Sixty-one adults (BMI 27–30 kg/m²) participated in a 16-week group-based, cognitive-behavioral control weight loss program. Concentrations of 12 fasting hormones and cytokines related to adiposity, satiety/hunger, and inflammation were measured using the Milliplex human metabolic human panel before and after weight loss. Participants were grouped based on ≥8% (successful group, SG) or <8% weight loss (less successful group, LSG). Results. The SG had 46 subjects (75.4%), while the LSG had 15 (24.6%). There were no differences in baseline sex distribution, age, weight, BMI, and body composition between groups. In the SG, baseline to the 16-week levels decreased significantly for c-peptide (1,030 versus 891 pg/mL, P = 0.002), insulin (665 versus 541 pg/mL, P = 0.001), and leptin (0.83 versus 0.58 ng/mL/kg fat, P < 0.001). None of the baseline analytes predicted greater weight loss. Conclusions. Successful weight loss was associated with changes in adiposity (less fat mass) and unfavorable hunger signals. No baseline biomarker profile was associated with weight loss success. Behavioral factors may have outweighed physiological signals for determining successful weight loss. This trial is registered with Clinicaltrials.gov NCT00429650.