Successful long-term weight maintenance: a 2-year follow-up

Objective: To find factors associated with successful weight maintenance (WM) in overweight and obese subjects after a very low‐calorie diet (VLCD). Research Methods and Procedures: Subjects (133) followed a VLCD (2.1 MJ/d) for 6 weeks in a free‐living situation. Of these, 103 subjects (age, 49.6 ± 9.7 years; BMI, 30.9 ± 3.8 kg/m²) completed the following 2‐year WM period. Body weight (BW), body composition, leptin concentration, attitude toward eating, and physical activity were determined right before (t0) and after (t1) the VLCD, after 3 months (t2), after 1 year (t3), after 1.5 years (t4), and after 2 years (t5). Results: BW loss during VLCD was 7.2 ± 3.1 kg. After 2 years, follow‐up BW regain was 69.0 ± 98.4%. After 2 years of WM, 13 subjects were successful (<10% BW regain), and 90 were unsuccessful (>10% BW regain). At baseline, these groups were significantly different in BMI (33.7 ± 4.7 vs. 30.5 ± 3.5 kg/m², respectively; p < 0.05) and fat mass (38.3 ± 9.8 vs. 32.1 ± 8.3 kg, p < 0.05). Successful subjects increased their dietary restraint significantly more during the whole study period (dietary restraint score, ?4.9 ± 4.4 vs. ?2.1 ± 3.8). Furthermore, %BW regain was associated with the amount of percentage body fat lost during VLCD, which indicates that the more fat lost, the better the WM, suggesting a fat free mass‐sparing effect. Discussion: Characteristics such as the ability to increase dietary restraint and maintain this high level of restraint, fat free mass sparing, and a relatively high baseline BMI and fat mass were associated with successful long‐term WM (<10% regain after 2 years).     

Genetic modulation of the serotonergic pathway: influence on weight reduction and weight maintenance

The serotonergic pathway plays a major role in the development of obesity. Its activity can be modulated by the 5-HT transporter–linked polymorphic region in the SLC6A4 gene and the upstream variable number of tandem repeats polymorphism in the MAOA gene. We studied whether these genetic modulations have an influence on weight reduction and weight maintenance in a one-year weight reduction program (OPTIFAST^®52). The polymorphisms were genotyped by PCR in a sample of 135 female and 67 male subjects with severe obesity (44 ± 13 years, 122.3 ± 22.2 kg, BMI: 41.7 ± 6.7 kg/m²). The program leads to a total weight loss of 19.9 ± 9.8 kg (16.9 ± 8.3 %) in women and 27.4 ± 13.6 kg (20.4 ± 9.9 %) in men. Anthropometric measurements and blood levels were determined at the start of the program (T0), after the weight reduction phase (T1) and after the subsequent weight maintenance phase at the end of the program (T2). Each polymorphism alone did not significantly influence weight loss or weight maintenance neither in men nor in women. However, women carrying both risk genotypes (SS and 3/3) displayed a lower total weight loss during the program (p = 0.05). This effect derived mainly from difficulties in the weight maintenance phase (p = 0.11), while the weight reduction phase was not affected (p = 0.61). No influence was found in men (p = 0.93). Modulation of the serotonergic pathway by carrying both risk alleles seems to influence success of weight loss programs in women with severe obesity due to problems in stabilizing body weight after weight reduction.     

Insulin Sensitivity as a Predictor of Weight Regain

A recent study found that increases in insulin sensitivity following weight loss and stabilization were strongly related to subsequent weight regain. The present paper analyzed this relationship in two behavioral weight-loss programs. In the first study, 125 nondiabetic subjects were followed over 30 months; weight losses averaged 10 kg at six months, and subjects had regained 8 kg of their weight loss by their 30-month follow-up. Neither fasting insulin levels at six months nor changes in fasting insulin from zero to six months were related to subsequent weight regain. Similarly, insulin levels measured two hours after a 75 g glucose load were unrelated to subsequent weight regain. The second study followed 33 individuals with Type II diabetes, treated with behavior modification, and either a low calorie diet or a very low calorie diet. Weight losses averaged 18 kg at six months, and subjects had regained 10 kg by their 24-month follow-up. The Bergman minimal model was used to assess insulin sensitivity at 6-month intervals. Initial analyses suggested that changes in insulin sensitivity from zero to six months were related to subsequent weight regain, but this effect was strongly influenced by an outlier. After removing this individual, there were no significant relationships between the changes in insulin sensitivity that accompanied weight loss and future weight regain. Likewise, insulin sensitivity at 12 months did not predict weight regain from 12 to 24 months. These data do not support the hypothesis that increases in insulin sensitivity with weight loss are associated with subsequent weight regain.     

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.     

A synaptic amplifier of hunger for regaining body weight in the hypothalamus

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