ABSTRACT
BACKGROUND: Chronic dieting syndrome can have negative physiologic and psychological consequences. Metabolic differences between female chronic dieters with normal and with low resting energy expenditures (REEs) have not been fully examined. OBJECTIVE: To determine whether differences existed between 2 groups (n = 15/group) of female chronic dieters aged 21-49 y with either normal (>/=100% of predicted) and with low (=85% of predicted) REEs based on the equation of Mifflin et al. DESIGN: The sample was a nonrandomized convenience sample and the 2 groups were compared in an observational study design. Body composition, aerobic fitness, physical activity, glucose and insulin responses, leptin and thyroid hormone status, dietary intake, and dietary restraint were measured. RESULTS: Both groups were similar with respect to age, height, weight, and body mass index. The normal-REE group had a higher lean body mass and insulin response to a test meal, higher thyroxine and reverse triiodothyronine concentrations, and lower dietary restraint. Within both groups, leptin decreased significantly from baseline to 2 h after an oral-glucose-tolerance test. The groups did not differ significantly with respect to dietary intake, aerobic fitness, or physical activity. CONCLUSIONS: Differences in insulin response were associated with higher ratios of abdominal to gluteal body fat in the normal-REE group. Leptin response appears to be due to normal diurnal variations in leptin production rather than a direct response to food consumption. It appears that a normal REE does not necessarily predict positive metabolic health among chronic dieters.
Subject(s)
Diet, Reducing , Energy Metabolism , Adipose Tissue , Adult , Blood Glucose/metabolism , Body Composition , Body Weight , Exercise , Fasting , Female , Humans , Insulin/blood , Kinetics , Leptin/analysis , Middle Aged , Oxygen Consumption , Physical Fitness , RestABSTRACT
The present investigation was undertaken to describe selected factors associated with the maintenance of body weight in three groups of women: relapsers (regained weight after losing weight), maintainers (maintained weight loss), and controls (weight stable). The following physiological variables were also assessed: resting energy expenditure (REE), serum glucose, insulin, leptin, triiodothyronine (T3), and body composition. As well, participants completed the interviewer-administered Weight Maintenance Questionnaire (WMQ). Overall, relapsers were older and heavier than maintainers and controls. As well, BMI, sum-of-four skinfolds, waist and arm circumference, serum leptin, and insulin levels were significantly greater for relapsers than for maintainers and controls. There were no differences between maintainers and controls in any of the parameters measured. Although relapsers revealed a history of weight cycling, the weight loss strategies and exercise habits of maintainers and relapsers did not differ. The data suggest that the higher body mass and fat mass in relapsers may explain the physiological differences between relapsers and maintainers.