Long-Term Weight Loss and Breakfast in Subjects in the National Weight Control Registry

Objective: To examine breakfast consumption in subjects maintaining a weight loss in the National Weight Control Registry (NWCR). Research Methods and Procedures: A cross-sectional study in which 2959 subjects in the NWCR completed demographic and weight history questionnaires as well as questions about their current breakfast consumption. All subjects had maintained a weight loss of at least 13.6 kg (30 lb) for at least 1 year; on average these subjects had lost 32 kg and kept it off for 6 years. Results: A large proportion of NWCR subjects (2313 or 78%) reported regularly eating breakfast every day of the week. Only 114 subjects (4%) reported never eating breakfast. There was no difference in reported energy intake between breakfast eaters and non-eaters, but breakfast eaters reported slightly more physical activity than non-breakfast eaters (p = 0.05). Discussion: Eating breakfast is a characteristic common to successful weight loss maintainers and may be a factor in their success.     

Internal Spatiotemporal Population Dynamics of Infection with Three Wolbachia Strains in the Adzuki Bean Beetle, Callosobruchus chinensis (Coleoptera: Bruchidae)

The adzuki bean beetle, Callosobruchus chinensis, is infected with three distinct lineages of endosymbiotic bacteria belonging to the genus Wolbachia, which were designated wBruCon, wBruOri, and wBruAus. In an attempt to understand the mechanisms underlying the infection with these three organisms, the spatiotemporal infection dynamics of the three Wolbachia strains was investigated in detail by using a quantitative PCR technique. During the development of C. chinensis, the wBruCon, wBruOri, and wBruAus infection levels consistently increased but the growth patterns were different. The levels of infection plateaued at the pupal stage at approximately 3 × 10⁸, 2 × 10⁸, and 5 × 10⁷ wsp copy equivalents per insect for wBruCon, wBruOri, and wBruAus, respectively. At the whole-insect level, the population densities of the three Wolbachia types did not show remarkable differences between adult males and females. At the tissue level, however, the total densities and relative levels of the three Wolbachia types varied significantly when different tissues and organs were compared and when the same tissues derived from males and females were compared. The histological data obtained by in situ hybridization and electron microscopy were concordant with the results of quantitative PCR analyses. Based on the histological data and the peculiar Wolbachia composition commonly found in nurse tissues and oocytes, we suggest that the Wolbachia strains are vertically transmitted to oocytes not directly, but by way of nurse tissue. On the basis of our results, we discuss interactions among the three coinfecting Wolbachia types, reproductive strategies of Wolbachia, and factors involved in the different cytoplasmic incompatibility phenotypes.     

Weight Loss and Leptin Changes in Individuals with Type 2 Diabetes

WILLIAMS, KATHERINE V., MONICA MULLEN, WE1 LANG, ROBERT V. CONSIDINE, AND RENA R. WING. Weight loss and leptin changes in individuals with type 2 diabetes. Obes Res. Objective To identify variables associated with leptin change in subjects with type 2 diabetes after 3 weeks and 20 weeks of weight loss. Research Methods and Procedures Subjects with type 2 diabetes treated with diet or sulfonylureas (n = 54) were enrolled in a 20-week behavioral weight control program. Sulfonylureas were stopped ≥2 weeks before study entry. Seven subjects who restarted sulfonylureas after week 3 had their data analyzed separately after this point. Results Leptin, fasting plasma glucose, and insulin levels were measured at baseline and at 3, 10, and 20 weeks. After 3 weeks, subjects lost 2.7±2.0 kg (p<0.001), and had significant decreases in leptin (5.2±7.0 ng/mL, p<0.001), fasting plasma glucose (1.8±1.8 mmol/L, p<0.001), and insulin (23±60 pmol/L, p<0.03). Between week 3 and week 20, subjects lost an additional 6.3±4.4 kg (P<0.001), but had no further changes in leptin. The primary determinants of leptin change at all time-points were weight loss and initial leptin level. Changes in insulin were not related to changes in leptin after controlling for the effects of weight loss. At week 20, more recent weight loss (week 10 to week 20) was as strong a predictor of overall change in leptin as overall weight loss (baseline to 20 week). Subjects who restarted sulfonylureas had an increase in both leptin levels (+1.9±9.0 ng/mL, p<0.05) and insulin levels (+23±65 pmol/L, p<0.05), despite significant overall weight loss (-7.4±4.0 kg, p<0.01). Initial changes in leptin (0 weeks to 3 weeks) did not affect subsequent ability to lose weight. Discussion Both short- and long-term changes in weight had an effect on leptin changes in individuals with type 2 diabetes. Although physiological insulin changes did not independently influence changes in leptin concentration with weight loss, increases in insulin levels with sulfonyl-urea therapy were associated with increases in leptin levels despite weight loss.     

Behavioral Strategies of Individuals Who Have Maintained Long-Term Weight Losses

MCGUIRE, MAUREEN T., RENA R. WING, MARY L. KLEM, AND JAMES O. HILL. Behavioral strategies of individuals who have maintained long-term weight losses. Obes Res. Objective: The purpose of the present study was to compare the behaviors of individuals who have achieved long-term weight loss maintenance with those of regainers and weight-stable controls. Research Methods and Procedures: Subjects for the present study were participants in a random-digit dial telephone survey that used a representative sample of the U. S. adult population. Eating, exercise, self-weighing, and dietary restraint characteristics were compared among weight-loss maintainers: individuals who had intentionally lost ≥10% of their weight and maintained it for ≥1 year (n = 69), weight-loss regainers: individuals who intentionally lost ≥10% of their weight but had not maintained it (n = 56), and weight-stable controls: individuals who had never lost ≥10% of their maximum weight and had maintained their current weight (±10 pounds) within the past 5 years (n= 113). Results: Weight-loss maintainers had lost an average of 37 pounds and maintained it for over 7 years. These individuals reported that they currently used more behavioral strategies to control dietary fat intake, have higher levels of physical activity (especially strenuous activity), and greater frequency of self-weighing than either the weight-loss regainers or weight-stable controls. Maintainers and regainers did not differ in reported levels of dietary restraint, but both had higher levels of restraint than the weight-stable controls. Discussion: These results suggest that weight-loss maintainers use more behavioral strategies to control their weight than either regainers or weight-stable controls. It would thus appear that long-term weight maintenance requires ongoing adherence to a low-fat diet and an exercise regimen in addition to continued attention to body weight.     

The Behavioral Characteristics of Individuals Who Lose Weight Unintentionally

MCGUIRE, MAUREEN T., RENA R. WING, MARY L. KLEM, AND JAMES O. HILL. The behavioral characteristics of individuals who lose weight unintentionally. Obes Res. Objective: To determine whether individuals who unintentionally lost weight differ from individuals who intentionally lost weight in behavioral characteristics related to chronic disease risk factors. Design: A random-digit dial telephone survey was conducted among a representative sample of American adults (n = 500). Subjects: Of the 500 individuals sampled, 139 were currently ≥10% below their lifetime maximum weight. These individuals were asked whether their weight loss was unintentional or intentional. Unintentional (n = 49) and intentional (n = 89) weight losers were compared on measures of dietary intake, physical activity, smoking, drinking, and self-reported health status. Results: Unintentional weight losers had higher levels of smoking and drinking, were less physically active, and were less concerned about their diet and fat intake. Unintentional weight losers did not report having higher levels of disease such as high blood pressure or diabetes. However, unintentional weight losers who reported having such diseases were more likely to report that their weight loss had no effect or had worsened their disorder. Discussion: Compared to intentional weight losers, those who lost their weight unintentionally reported engaging in more negative health behaviors that are related to disease morbidity and mortality. These data suggest that unintentional weight loss may be part of a cluster of behaviors that have a negative health impact.