Background:The prevalence of obesity is higher in black than in white women. Differences in energy economy and physical activity may contribute to this difference. Objective: The objective of this study was to compare free-living energy expenditure and physical activity in black and white women before and after weight loss. Design: Participants were 18 white and 14 black women with body mass indexes (in kg/m 2 ) between 27 and 30. Diet, without exercise, was used to achieve a weight loss of ≥ 10 kg and a body mass index < 25. After 4 wk of energy balance in overweight and normal-weight states, body composition was assessed by using a 4-compartment model, sleeping and resting energy expenditures were assessed by using a chamber calorimeter, physiologic stress of exercise and exercise economy were measured by using standardized exercise tasks, and daily energy expenditure was assessed by using doubly labeled water. Results: Weight loss averaged 12.8 kg. Sleeping and resting energy expenditures decreased in proportion to changes in body composition. Weight reduction significantly improved physiologic capacity for exercise in both groups of women, making it easier for them to be physically active. Black women had lower body composition-adjusted energy requirements than did white women-both before and after weight loss-during sleep (9% lower, 519 kJ/d; P < 0.001), at rest (14% lower, 879 kJ/d; P < 0.001), during exercise (6% lower; P < 0.05), and as a daily total (9% lower, 862 kJ/d; P < 0.06). By contrast, free-living physical activity was similar between the groups. Conclusions: Weight-reduced women had metabolic rates appropriate for their body sizes. Black women had lower resting and nonresting energy requirements in both overweight and normalweight states than did white women and did not compensate with greater physical activity, potentially predisposing them to greater weight regain.

The purpose of this study was to examine the effects of a total body strength-training program on changes in total and regional body composition, in particular intra-abdominal adipose tissue (IAAT), in older women. Fourteen healthy older women (mean age 67 +/- 1 yr) exercised 3 times/wk for 16 wk. Strength was assessed by one-repetition maximum tests, with training intensity gradually increased to approximately 67% of one repetition maximum. Body composition was measured by hydrodensitometry and regional body composition was measured by computed tomography. Strength was significantly increased in the upper (51%) and lower body (65%). There was no significant change in body weight (64.4 +/- 2.7 vs. 64.2 +/- 2.7 kg), total body fat (38.7 +/- 1.4 vs. 38.0 +/- 1.6%) or fat-free mass (39.7 +/- 1.0 vs. 40.0 +/- 0.9 kg). However, after ST, there were significant reductions in IAAT (143.9 +/- 13.3 vs. 130.0 +/- 12.4 cm2), the IAAT-to-subcutaneous adipose tissue ratio (0.48 +/- 0.04 vs. 0.44 +/- 0.04), and midthigh subcutaneous adipose tissue (141.7 +/- 11.5 vs. 133.6 +/- 10.8 cm2) and an increase in midthigh muscle (52.9 +/- 2.6 vs. 58.0 +/- 2.0 cm2) (all P < 0.05). In conclusion, significant reductions in IAAT and an increase in strength and muscle area were observed after a strength-training program in healthy older women. These changes may be important in preventing the negative health outcomes associated with the age-related increase in intra-abdominal obesity.

OBJECTIVE: To examine whether body fat content in pre-pubertal children is in¯uenced by physical activity related energy expenditure (AEE) and/or more qualitative aspects of physical activity. DESIGN: Cross-sectional study. SUBJECT: 101 pre-pubertal children were examined in Study 1: (age: 5.3 AE 0.9 y; weight: 20.2 AE 3.6 kg). In Study 2: 68 of the original children were re-examined (age: 6.3 AE 0.9 y; weight: 23.6 AE 5.0 y). MEASUREMENT: Fat mass (FM) and fat free mass (FFM) were determined by bioelectrical resistance and skinfolds; AEE was estimated from the difference between total energy expenditure (TEE) by doubly labeled water and postprandial resting energy expenditure (REE) by indirect calorimetry; qualitative information on activity was derived by questionnaire. RESULTS: AEE was signi®cantly correlated with FFM (r 0.32 in both Studies) and body weight (r 0.28 in Study 1; r 0.29 in Study 2), but not FM. There were no signi®cant relationships between AEE and any of the variables from the activity questionnaire in children (including TV time, playing time, and an accumulated activity index in h/ week). After adjusting for FFM, age, and gender, FM was inversely related to activity time in h/week (partial r 70.24 in Study 1; partial r 70.32 in Study 2) but not AEE (P b 0.5). CONCLUSION: After adjusting for FFM, age, and gender, a small portion of the variance in body fat mass in children ( $ 10%) is explained by time devoted to recreational activity, whereas none of the variance is explained by the combined daily energy expenditure related to physical activity.

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