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.     

Direct and correlated responses to selection for weaning weight,post-weaning weight gain and six-week weight in mice

Summary Four lines of mice were formed from a common base population and selected for 37 generations for either increased 3-week weight (weaning weight), 6-week weight, 3–6 week gain, or maintained as a randomly bred control line. Realised heritability estimates for short-term (long-term) responses were 0.33±0.20 (0.07±0.10), 0.46±0.14 (0.26±0.09), 0.36±0.14 (0.24±0.11) for 3-week weight, 6-week weight and 3–6 week gain, respectively. Realised genetic correlations estimated from short-term (long-term) responses were 0.23±0.08 (0.35±0.10) between 3-week weight and 3–6 week gain; 0.82±0.04 (0.58±0.08) between 3-week weight and 6-week weight; and 0.81±0.04 (0.97±0.04) between 3–6 week gain and 6-week weight. The genetic correlation between 3-week weight and 6-week weight was asymmetric with a greater correlated response for 3-week weight when selecting for 6-week weight (1.06) than vice versa (0.63).     

Average molecular weight and molecular weight distribution of agarose and agarose-type polysaccharides

A procedure to determine the absolute weight-average molecular weight and molecular weight distribution of agarose and agarose-type polysaccharides by aqueous size-exclusion chromatography coupled with low-angle laser light scattering is described. The molecular weights of the majority of the commercial samples investigated were between 80 000 and 140 000 with a polydispersity lower than 1·7. In contrast, most of the laboratory-extracted agarose-type polysaccharides had lower molecular weights.     

Testes weight, body weight and mating systems in marsupials and monotremes

Relationships between testes weight, body weight and mating systems were examined in 40 marsupial species and in the extant monotremes. Relationships between relative testes weight and mating systems in marsupials resemble those previously described for primates. Thus relative testes weights are greatest in those marsupials where females mate with multiple males during the fertile period, i.e. polyandrous species (e.g. Antechinus ftavipes, Isoodon obesulus, Perameles nasuta, Potorous tridactylus, Macropus eugenii and M. agilis) and smallest in monandrous forms (e.g. Petauroides volans and Petaurus breviceps ) where females usually mate with a single male. These findings are consistent with effects of sperm competition upon the evolution of relative testes sizes in marsupials. Where field studies on marsupial mating systems are lacking, we make predictions based upon examination of their relative testes weights. Tarsipes rostratus, Acrobates pygmaeus, Macropus rufogriseus and Sarcophilus harrisii are predicted to engage in multiple matings and sperm competition. Conversely, Lasiorhinus latifrons, Cercatetus concinnus and Pseudoantechinus macdonnellensis are predicted to be monandrous in their mating behaviour. The monotremes ( Ornithorhynchus anatinus, Tachyglossus aculeatus and Zaglossus bruijnii ) are characterized by possession of very large testes; monotremes are shown to have significantly greater relative testes weights than marsupials, primates or avian species. This taxonomic difference is unlikely to be related lo the occurrence of oviparity or to the abdominal position of the testes in the Monotremata. Their mating systems are not known in detail, but some evidence for multiple matings (and hence for sperm competition) exists for Tachyglossus aculeatus so that their large testes may be adaptive in this context.     

Hyperphenylalaninemia and birth weight

Hyperphenylalaninemias (HPAs) are due to autosomal recessive inherited deficiency of phenylalanine hydroxylase and include three different biochemical and clinical phenotypes: classic phenylketonuria, mild phenylketonuria and persistent HPA. Recently the relationship between birth weight and HPA has been investigated. We performed an evaluation of birth weight in our 260 HPA patients. Our results do not support the view that birth weight is reduced in HPA patients and we found no correlation between birth weight and severity of the disease. Only a better knowledge of genetic mechanisms involved in HPA can clarify the interaction between HPA and fetal development.     

A low molecular weight antioxidant decreases weight and lowers tumor incidence

Stable free radical nitroxides are potent antioxidants possessing superoxide dismutase- and catalase-mimetic activity that protect cells and animals against a variety of oxidative insults. Tempol, as a representative nitroxide, was evaluated for its influence on weight maintenance and spontaneous tumor incidence in C3H mice. Tempol administered in either the drinking water or food did not show any untoward effects and prevented animals from becoming obese. Tempol-treated animals' leptin levels were reduced. Long-term treatment with Tempol significantly decreased tumorigenesis when compared to controls (10 vs. 40%, respectively). Selected tissues from Tempol-treated animals exhibited elevated levels of mitochrondrial uncoupling protein-2 (UCP-2) and HSP70. The present data suggest that nitroxides upregulate UCP-2, obviate weight gain, and decrease age-related spontaneous tumor incidence. As a class, nitroxides may provide overall health benefits by contributing to decreased obesity and tumor incidence.     

Predictors of attrition and weight loss in an adolescent weight control program

Objective: To evaluate demographic and psychosocial predictors of attrition and weight loss in a behaviorally based adolescent weight control trial. Methods and Procedures: Adolescents (N = 76) aged 13–16 years and 20–80% overweight (M = 60.56%, s.d. = 15.17%) received standard group‐based behavioral treatment as part of a randomized trial comparing different activity interventions for overweight adolescents. Anthropometric and psychosocial measures were obtained at baseline and after the 16‐week intervention. Results: Higher parent (P < 0.01) and adolescent BMI (P < 0.05) at baseline, as well as ethnic minority status (P < 0.05) were significantly associated with attrition in univariate analyses. Parent BMI remained the only significant predictor of attrition in multivariate analyses. BMI change for completers (N = 62) was highly variable, ranging from ?6.09 to +1.62 BMI units. Male gender (P < 0.01) was a significant predictor of reduction in BMI, whereas not being from an ethnic minority group (P < 0.05) and attendance at group sessions (P = 0.05) were associated with ≥5% absolute weight loss in multivariate analyses. Absolute weight loss during the first 4 weeks of the program was strongly associated with weight loss (pr = 0.44, P < 0.001) during the remainder of the intervention. Psychosocial variables were unrelated to attrition or treatment outcome. Discussion: These findings highlight the potential importance of attending to parental BMI in efforts to retain adolescent participants in treatment, as well as the need to develop weight control interventions that are more effective for ethnic minority youth.     

Dietary adherence during weight loss predicts weight regain

This study examined the relationship between previous dietary adherence during a low-calorie diet weight loss intervention and subsequent weight change during a 2-year follow-up for weight maintenance. One hundred and sixteen healthy, recently weight reduced (lost ~12 kg, BMI 22-25 kg/m2) premenopausal women were studied. Dietary adherence was assessed by doubly labeled water (DLW) and body composition change. Comparisons were made between the upper and lower tertiles for previous dietary adherence and subsequent weight change at 1- and 2-year follow-up. Percent weight regained was significantly lower (30.9 ± 6.7% vs. 66.7 ± 9.4%; P < 0.05) in the upper compared to the lower adherence tertile for previous weight loss dietary adherence (49.9 ± 8.8% vs. 96.8 ± 12.8% P < 0.05) at 1- and 2-year follow-up, respectively. This difference was partly explained by increases in daily activity-related energy expenditure (AEE) (+95 ± 45 kcal/day vs. -44 ± 42 kcal/day, P < 0.05) and lower daily energy intake (2,066 ± 71 kcal/day vs. 2,289 ± 62 kcal/day, P < 0.05) in the higher tertile for previous dietary adherence, compared to the lower. These findings suggest that higher adherence (i.e., higher tertile) to the previous low-calorie diet predicts lower weight regain over 2-year follow-up for weight maintenance, which is explained by lower energy intake and higher physical activity. Finally, how well an individual adheres to a low-calorie diet intervention during weight loss may be a useful tool for identifying individuals who are particularly vulnerable to subsequent weight regain.     

Relative weight and sickness absence

Objectives: To examine whether high relative weight increases the risk of future sickness absence and to what extent any differences in short and long absence periods can be explained by specific obesity‐related disorders, general health, and working conditions. Research Methods and Procedures: The study included 5386 female and 1452 male employees of the city of Helsinki surveyed in 2000 to 2002. Survey data were linked to sickness absence records until the end of 2004 (mean follow‐up time 2.9 years). Results: Women and men with higher relative weight had clearly more short (1 to 3 days) and long (>3 days) periods of sickness absence during follow‐up. The associations were rather monotonic and stronger for long periods. In women, adjusting for arthrosis and gout decreased the excess risk of long periods among those who were obese. In men, arthrosis, gout, and metabolic disease explained some of the excess risk for both short and long periods among the obese. Adjusting for physical functioning and self‐rated health decreased the excess risk for short and long periods of sickness absence among obese women and men. Working conditions had almost no effect on the association between BMI and short or long periods of sickness absence. Discussion: Obesity increases the risk of having short and long periods of sickness absence. This finding can be partly explained by measures of general health and specific obesity‐related disorders. Healthy weight maintenance is a crucial issue in promoting occupational functioning and minimizing the costs associated with sickness absence.     

Personality disorders and body weight

We examine the impact of Axis II personality disorders (PDs) on body weight. PDs are psychiatric conditions that develop early in life from a mixture of genetics and environment, are persistent, and lead to substantial dysfunction for the affected individual. The defining characteristics of PDs conceptually link them with body weight, but the direction of the relationship likely varies across PD type. To investigate these links, we analyze data from Wave II of the National Epidemiological Survey of Alcohol and Related Conditions. We measure body weight with the body mass index (BMI) and a dichotomous indicator for obesity (BMI ≥ 30). We find that women with PDs have significantly higher BMI and are more likely to be obese than otherwise similar women. We find few statistically significant or economically meaningful effects for men. Paranoid, schizotypal, and avoidant PDs demonstrate the strongest adverse impacts on women's body weight while dependent PD may be protective against elevated body weight among men. Findings from unconditional quantile regressions demonstrate a positive gradient between PDs and BMI in that the effects are greater for higher BMI respondents.     

Three-year weight change in successful weight losers who lost weight on a low-carbohydrate diet

Objective: The purpose of this study was to evaluate long‐term weight loss and eating and exercise behaviors of successful weight losers who lost weight using a low‐carbohydrate diet. Research Methods and Procedures: This study examined 3‐year changes in weight, diet, and physical activity in 891 subjects (96 low‐carbohydrate dieters and 795 others) who enrolled in the National Weight Control Registry between 1998 and 2001 and reported ≥30‐lb weight loss and ≥1 year weight loss maintenance. Results: Only 10.8% of participants reported losing weight after a low‐carbohydrate diet. At entry into the study, low‐carbohydrate diet users reported consuming more kcal/d (mean ± SD, 1895 ± 452 vs. 1398 ± 574); fewer calories in weekly physical activity (1595 ± 2499 vs. 2542 ± 2301); more calories from fat (64.0 ± 7.9% vs. 30.9 ± 13.1%), saturated fat (23.8 ± 4.1 vs. 10.5 ± 5.2), monounsaturated fat (24.4 ± 3.7 vs. 11.0 ± 5.1), and polyunsaturated fat (8.6 ± 2.7 vs. 5.5 ± 2.9); and less dietary restraint (10.8 ± 2.9 vs. 14.9 ± 3.9) compared with other Registry members. These differences persisted over time. No differences in 3‐year weight regain were observed between low‐carbohydrate dieters and other Registry members in intent‐to‐treat analyses (7.0 ± 7.1 vs. 5.7 ± 8.7 kg). Discussion: It is possible to achieve and maintain long‐term weight loss using a low‐carbohydrate diet. The long‐term health effects of weight loss associated with a high‐fat diet and low activity level merits further investigation.     

Insulin resistance and birth weight

This review article describes the scientific evidence for the relationship between birth weight and insulin resistance. Most studies demonstrate that low birth weight is closely connected to insulin resistance and later development of diabetes type II in adulthood. For this reason it is important for clinicians to focus on the personal history of the patient's birth weight. In patients with low birth weight, primary measures should be taken to prevent the development or progress of insulin resistance, and late consequences like diabetes and atherosclerotic complications.