Internal disinhibition predicts weight regain following weight loss and weight loss maintenance

Objective: The disinhibition scale of the Eating Inventory predicts weight loss outcome; however, it may include multiple factors. The purpose of this study was to examine the factor structure of the disinhibition scale and determine how its factors independently relate to long‐term weight loss outcomes. Research Methods and Procedures: Exploratory factor analysis of the disinhibition scale was conducted on 286 participants in a behavioral weight loss trial (TRIM), and confirmatory factor analysis was conducted on 3345 members of the National Weight Control Registry (NWCR), a registry of successful weight loss maintainers. Multivariate regressions were used to examine the relationships between the disinhibition scale factors and weight over time in both samples. Results: Using baseline data from TRIM, two factors were extracted from the disinhibition scale: 1) an “internal” factor that described eating in response to internal cues, such as feelings and thoughts; and 2) an “external” factor that described eating in response to external cues, such as social events. This factor structure was confirmed using confirmatory factor analysis in the NWCR. In TRIM, internal disinhibition significantly predicted weight loss at 6 months (p = 0.03) and marginally significantly predicted weight loss at 18 months (p = 0.06), with higher levels of internal disinhibition at baseline predicting less weight loss; external disinhibition did not predict weight loss at any time‐point. In NWCR, internal disinhibition significantly predicted one‐year weight change (p = 0.001), while external disinhibition did not. Discussion: These results suggest that it is the disinhibition of eating in response to internal cues that is associated with poorer long‐term weight loss outcomes.     

Successful weight-loss maintenance in relation to method of weight loss

This study examined the relation between method of weight loss and long-term maintenance among successful weight losers enrolled in a weight-loss maintenance trial. Participants were 186 adults (mean age = 51.6 +/- 10.7 years, mean BMI = 28.6 +/- 4.7 kg/m(2)) enrolled in the STOP Regain trial who had lost at least 10% of their body weight in the past 2 years using a very low-calorie diet (VLCD; n = 24), commercial program (n = 95), or self-guided approach (n = 67). Participants were randomized to a weight-maintenance intervention delivered face to face or over the internet or to a newsletter control condition, and followed for 18 months. At study entry, individuals who had used a VLCD had achieved a weight loss of 24% of their maximum weight within the past 2 years compared to 17% achieved by those who had used a commercial program or self-guided approach (P < 0.001). However, individuals who had used a VLCD regained significantly more weight than the other two groups and by 6 months, there were no significant differences in overall percent weight loss (i.e., initial weight loss and maintenance) between VLCD, commercial, and self-guided methods. In contrast, individuals who had used a self-guided approach maintained their weight losses from baseline through 18 months. The large initial weight losses achieved by individuals who had used a VLCD were not maintained over time, whereas individuals who had used a self-guided approach maintained their initial weight losses with the greatest success. The generalizability of these findings is limited by the sizeable weight losses achieved by study participants.     

Consistent self-monitoring of weight: a key component of successful weight loss maintenance

Objective: The objectives were to investigate the characteristics associated with frequent self‐weighing and the relationship between self‐weighing and weight loss maintenance. Research Methods and Procedures: Participants (n = 3003) were members of the National Weight Control Registry (NWCR) who had lost ≥30 lbs, kept it off for ≥1 year, and had been administered the self‐weighing frequency assessment used for this study at baseline (i.e., entry to the NWCR). Of these, 82% also completed the one‐year follow‐up assessment. Results: At baseline, 36.2% of participants reported weighing themselves at least once per day, and more frequent weighing was associated with lower BMI and higher scores on disinhibition and cognitive restraint, although both scores remained within normal ranges. Weight gain at 1‐year follow‐up was significantly greater for participants whose self‐weighing frequency decreased between baseline and one year (4.0 ± 6.3 kg) compared with those whose frequency increased (1.1 ± 6.5 kg) or remained the same (1.8 ± 5.3 kg). Participants who decreased their frequency of self‐weighing were more likely to report increases in their percentage of caloric intake from fat and in disinhibition, and decreases in cognitive restraint. However, change in self‐weighing frequency was independently associated with weight change. Discussion: Consistent self‐weighing may help individuals maintain their successful weight loss by allowing them to catch weight gains before they escalate and make behavior changes to prevent additional weight gain. While change in self‐weighing frequency is a marker for changes in other parameters of weight control, decreasing self‐weighing frequency is also independently associated with greater weight gain.     

1,3-Butadiene working group report

During the Workshop in North Carolina, the in vivo metabolism, adduct formation and genotoxicity data available from rodent and human exposure to 1,3-butadiente (BD) were reviewed and they are summarized in the present report. BD is metabolized by cytochrome P-450-dependent monoxygenases to the primary metabolite 1,2-epoxybutene-3 (epoxybutene, EB). EB is subjected to further metabolism: oxidation to 1,2:3,4-diepoxybutane (DEB), hydrolysis to 3-butene-1,2-diol and conjugation to glutathione. The first pathway seems to prevail in mice while the latter is characteristic for rats and possibly for humans. Species differences exist in adduct formation of the monoepoxide to hemoglobin, for which the following pattern has been found: mice > rats > humans. Genotoxity of BD was found in mice with all applied tests; however, negative results were obtained in rats. In exposed humans, the cytogenetic studies in peripheral blood lymphocytes did not show genotoxic effects, although one report described elevated hprt variant levels in peripheral blood lymphocytes of exposed workers.

It was concluded that the presently available data are insufficient for the application of the parallelogram model to estimate genetic risk for humans. As an alternative approach, a tentative estimate of the doubling dose for induction of hprt mutations in somatic cells of mice and men was performed and the calculated values were surprisingly similar, i.e. 9000 ppmh. However, this estimate is burdened with a number of caveats which were discussed in detail. The working group identified a series of urgent research needs to provide the appropriate data for the application of the parallelogram model, such as identification of metabolic pathways in different rodent species and humans, metabolic studies in mice, rats and humans considering metabolic polymorphisms, studies of adducts to DNA and hemoglobin especially of DEB and other butadiene metabolites in rodents and humans, studies of mutational spectra (mutational fingerprinting) in somatic and germinal cells, confirmation of the human hprt mutation data, confirmation of the rodent malformation data, dose-response studies in rodent germ cell tests and studies on repair kinetics of mono-adducts induced by EB as opposed to repair of cross-links produced by DEB. Finally, it was suggested that the original parallelogram consisting of data from somatic cell studies in rodents and humans plus studies of heritable effects in rodents to extrapolate to germ cell risk for humans should be supplemented with studies in sperm of experimental animals and exposed men.     

Failure to meet weight loss expectations does not impact maintenance in successful weight losers

Objective: The objective was to examine whether having a weight loss experience that lives up to one's expectations is related to maintenance in a group of successful weight losers participating in the STOP Regain trial. Research Methods and Procedures: Participants (N = 314, 81% women, mean age, 51.3 ± 10.1 years; BMI = 28.6 ± 4.8 kg/m²) who lost ≥10% of their body weight within the past 2 years were randomly assigned to a maintenance program delivered either face‐to‐face or via the Internet or to a control group and assessed at 0, 6, 12, and 18 months. Results: At study entry, participants had lost 19% of their body weight, yet 86% of participants were currently trying to lose more weight. Further losses of 13% of body weight were needed to reach self‐selected ideal weights, with heavier participants wanting to lose more (p < 0.001). The weight loss‐related benefits participants achieved did not live up to their expectations (p ≤ 0.01). However, neither satisfaction with current weight, nor amount of further weight loss desired, nor discrepancies between actual and expected benefits predicted regain after adjusting for treatment group, gender, baseline weight, and percent weight loss before entry. Discussion: Even among very successful weight losers, expectations were not met and substantial further weight losses were desired; however, these factors were not related to subsequent weight maintenance outcomes.     

Predictors of successful long-term weight loss maintenance: a two-year follow-up

Background

Weight regain is a common problem following weight loss intervention, with most people who seek treatment for obesity able to lose weight, but few able to sustain the changes in behavior required to prevent subsequent weight regain. The identification of factors that predict which patients will successfully maintain weight loss or who are at risk of weight regain after weight loss intervention is necessary to improve the current weight maintenance strategies. The aim of the present study is identify factors associated with successful weight loss maintenance by women with overweight or obesity who completed group cognitive behavioral treatment (CBT) for weight loss.

Methods

Ninety women with overweight or obesity completed a 7-month weight loss intervention. The data of 86 who completed follow-up surveys 12 and 24 months after the end of the treatment was analyzed. Depression, anxiety, binge eating, food addiction, and eating behaviors were assessed before and after the weight loss intervention. Participants who lost at least 10% of their initial weight during the weight loss intervention and had maintained the loss at the month 24 follow-up were defined as successful.

Results

The intervention was successful for 27 participants (31.3%) and unsuccessful for 59 (68.6%). Multiple logistic regression analysis extracted larger weight reduction during the weight loss intervention, a lower disinhibition score, and a low food addiction score at the end of the weight loss intervention as associated with successful weight loss maintenance.

Conclusion

The results suggest that larger weight reduction during the weight loss intervention and lower levels of disinhibition and food addiction at the end of the weight loss intervention predicted successful weight loss maintenance.

Trial registration

Trial registry name: Development and validation of effective treatments of weight loss and weight-loss maintenance using cognitive behavioral therapy for obese patients.Registration ID: UMIN000006803Registered 1 January 2012.URL: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000008052

     

The failure of therapist assistance and stepped-care to improve weight loss outcomes

Objective: This investigation was designed to examine whether: (i) individuals could successfully lose 5% of their body weight with minimal assistance, (ii) weight loss would be improved by the addition of therapist assistance, and (iii) individuals unsuccessful at losing 5% total body weight during the minimal assistance phase (with or without therapist assistance) would benefit from a weekly weight loss group. Methods and Procedures: Fifty‐four overweight or obese adults (BMI > 27 kg/m²) initially participated in a 14‐week self‐help (SH) or therapist‐assisted SH (TASH) weight loss program. Participants who were unsuccessful at losing 5% total body weight were stepped‐up to a 3‐month, group‐based behavioral weight loss program (BWLP) with weekly weigh‐ins. Results: Although ～60% of the participants were successful at losing 5% of their total body weight (lb) during the minimal assistance phase (M = 10.6; s.d. = 11.5; P < 0.01), treatment outcome was not improved by the addition of therapist assistance. For individuals who were unsuccessful at losing 5% of total body weight during a minimal assistance phase, the addition of a group‐based BWLP did not improve their weight loss. Discussion: While many individuals were quite successful at losing weight with minimal assistance, other individuals evidenced difficulties losing weight, even when participating in a greater intensity intervention (i.e., BWLP group).     

Rise of plasma ghrelin with weight loss is not sustained during weight maintenance

Objective: Ghrelin is postulated to be an orexigenic signal that promotes weight regain after weight loss (WL). However, it is not known whether this putative effect of ghrelin is sustained after weight stabilization. The objective of this study was to investigate the relationship of plasma ghrelin concentrations to active WL and weight maintenance in obese subjects. Research Methods and Procedures: This study was a randomized clinical trial, with a 12‐month follow‐up period. Obese Mexican‐American women matched for age and BMI were randomized to a 12‐month WL program (n = 25) or no intervention (controls, n = 23). Interventions included diet, exercise, and orlistat. Body weight and fasting ghrelin, leptin, insulin, and glucose concentrations were measured at baseline and 6 and 12 months. Results: The WL group lost 8.5% of body weight after 6 months and maintained the new weight for the next 6 months. Ghrelin concentrations increased significantly at 6 months but returned to baseline at 12 months. Baseline ghrelin concentrations were directly related to the degree of WL achieved after 12 months. Controls experienced no change in BMI or ghrelin levels. There were no associations between plasma ghrelin and leptin or insulin concentrations. Discussion: Consistent with previous results, ghrelin rises in response to WL, perhaps as a counterregulatory mechanism. However, the present results indicate that ghrelin concentrations return to baseline with sustained weight maintenance, suggesting that its effects are unlikely to regulate long‐term energy balance. Baseline ghrelin concentrations are related to the degree of WL that can be achieved by active weight reduction.     

Role of hereditary factors in weight loss and its maintenance

The prevalence of obesity is increasing worldwide at an alarming rate in both developed and developing countries. Obesity is a chronic complex disease of multifactorial origin resulting from a long-term positive energy balance, in which both genetic and environmental factors are involved. Genetically prone individuals are the first to accumulate fat in the present obesogenic environment. Obesity increases the risks of type 2 diabetes, hypertension, cardiovascular disease, dyslipidemia, arthritis, and several cancers and reduces the average life expectancy. Implementation of effective strategies in prevention and management of obesity should become an important target in health care systems. Weight changes throughout life depend on the interaction of behavioral, genetic and environmental factors. Weight loss in response to weight management shows a wide range of interindividual variation which is largely influenced by genetic determinants. The strong control of weight loss by genotype was confirmed by twin and family studies. Recently, special attention has been paid to nutritional, hormonal, psychobehavioral and genetic factors which can predict the response to weight reduction programme. In this article currently available data on the role of obesity candidate gene polymorphisms in weight loss and maintenance are reviewed. It is believed that an elucidation of the genetic component in the prognosis of weight management could assist in the development of more effective and individually tailored therapeutic strategies.     

Aerobic exercise is necessary to improve glucose utilization with moderate weight loss in women

Objective: To determine the effects of weight loss (WL) alone and combined with aerobic exercise on visceral adipose tissue (VAT), intramuscular fat, insulin‐stimulated glucose uptake, and the rate of decline in free fatty acid (FFA) concentrations during hyperinsulinemia. Research Methods and Procedures: We studied 33 sedentary, obese (BMI = 32 ± 1 kg/m²) postmenopausal women who completed a 6‐month (three times per week) program of either WL alone (n = 16) or WL + aerobic exercise (AEX) (n = 17). Glucose utilization (M) was measured during a 3‐hour hyperinsulinemic‐euglycemic clamp (40 mU/m² per minute). M/I, the amount of glucose metabolized per unit of plasma insulin (I), was used as an index of insulin sensitivity. Results: Body weight, total fat mass, and percentage fat decreased similarly in both groups (p < 0.01). VAT, subcutaneous abdominal adipose tissue, mid‐thigh subcutaneous fat, and intramuscular fat decreased to a similar extent in both groups and between 14% and 27% after WL and WL+AEX (p < 0.05). WL alone did not change M or M/I; however, M and M/I increased 15% and 21% after WL+AEX (p < 0.05). Fasting concentrations and rate of decline of FFA did not change in either group. In stepwise regression models to determine the independent predictors of changes in M and M/I, the change in VAT was the single independent predictor of M (r² = 0.30) and M/I (r² = 0.33). Discussion: Intramuscular fat decreases similarly with 6 months of moderate WL alone or with aerobic exercise in postmenopausal women. In contrast, only WL combined with exercise results in increased glucose utilization and insulin sensitivity. These findings should be validated in a larger population.