Physical activity in free-living,overweight white and black women: divergent responses by race to diet-induced weight loss

BACKGROUND: Black women are at greater risk of obesity than are white women, perhaps because of their lower levels of physical activity. OBJECTIVE: We compared free-living activity energy expenditure (AEE) in sedentary white and black women (in overweight and normal-weight states) and in never-overweight control subjects. DESIGN: Subjects included 46 women (23 white, 23 black) studied while overweight and after reaching a normal weight and 38 female control subjects (23 white, 15 black). Diet, without exercise training, resulted in a mean weight loss of 13 kg and a body mass index (in kg/m(2)) < 25. Body composition, sleeping energy expenditure, free-living total energy expenditure, and the energy cost of activity and aerobic capacity were assessed before and after weight loss under 4-wk, diet-controlled, weight-stable conditions and in the control subjects. AEE was defined as above-sleep energy expenditure. RESULTS: No significant racial differences in body composition, before or after weight loss, were found. After weight loss, AEE and aerobic capacity increased in the white women and decreased in the black women (P < 0.05 and P < 0.02, respectively). After weight loss, but not before, the white women had a significantly higher mean AEE than did the black women (2448 +/- 979 and 1728 +/- 1373 kJ/d, respectively; P < 0.05), approximating AEEs in the white (2314 +/- 1105) and black (2310 +/- 1251) control subjects. CONCLUSIONS: Relative to the responses of the white women to diet-induced weight loss, the black women became less fit and less physically active. Induction of a normal body weight in overweight black women appeared to produce a more obesity-prone state, favoring weight relapse.     

Racial differences in metabolic predictors of obesity among postmenopausal women.

OBJECTIVE: This study determined whether there are racial differences in resting metabolic rate (RMR), fat oxidation, and maximal oxygen consumption (VO2max) in obese [body mass index (BMI = 34+/-2 kg/m2)], postmenopausal (58+/-2 years) women. RESEARCH METHODS AND PROCEDURES: Twenty black and 20 white women were matched for fat mass and lean mass (LM), as determined by dual energy X-ray absorptiometry. RMR and fat oxidation were measured by indirect calorimetry in the early morning after a 12-hour fast using the ventilated hood technique. VO2max was measured on a treadmill during a progressive exercise test to voluntary exhaustion. RESULTS: RMR, adjusted for differences in LM, was 5% higher in white than black women (1566+/-27 and 1490+/-26 kcal/day, respectively; p<0.05); and fat oxidation rate was 17% higher in white than black women (87+/-4 and 72+/-3 g/day, respectively; p<0.01). VO2max (L/minute) was 150 mL per minute (8%) higher (p<0.05) in white than black women. VO2max correlated with LM in black (r=0.44, p=0.05) and white (r=0.53, p<0.05) women, but the intercept of the regression line was higher in white than black women (p<0.05), with no significant difference in slopes. In a multiple regression model including race, body weight, LM, and age, LM was the only independent predictor of RMR (r2 = 0.46, p<0.0001), whereas race was the only independent predictor of fat oxidation (r2 = 0.18, p<0.05). The best predictors of VO2max were LM (r2 = 0.22, p<0.05) and race (cumulative r2 = 0.30, p<0.05). DISCUSSION: These results show there are racial differences in metabolic predictors of obesity. Determination of whether these ethnic differences lead to, or are an effect of, obesity status or other lifestyle factors requires further study.     

Predictors of weight maintenance

OBJECTIVE: To obtain predictors of weight maintenance after a weight-loss intervention. RESEARCH METHODS AND PROCEDURES: An overall analysis of data from two-long intervention studies [n=67 women; age: 37.9+/-1.0 years; body weight (BW): 87.0+/-1.2 kg; body mass index: 32.1+/-0.5 kg.m(-2); % body fat: 42.4+/-0.5%]. Subjects were measured before a very low energy diet (month 0), after the very low energy diet of 2 months (month 2) and after a 14-month follow-up phase (at 16 months), in which fiber or a carbohydrate-containing food supplement was supplied. The baseline measurements and the changes in parameters induced by the diet intervention were used to predict the changes in BW in the follow-up phase [deltaBW(2-16)]. RESULTS: Multiple regression analysis revealed that 50% (p<0.001) of the variability in weight regain could be explained by physiological and behavioral factors. These were: frequency of previous dieting (r2=0.27, p<0.05), hunger score (measured with the three-factor eating behavior questionnaire), and change in 24-hour resting metabolic rate (RMR). Frequent dieters showed significantly more weight regain than less frequent dieters (8.8+/-1.0 kg vs. 5.1+/-0.8 kg, p<0.01). Subjects having parents with obesity regained almost significantly more weight than subjects with lean parents (8.5+/-0.2 kg vs. 5.1+/-1.5 kg, respectively; p = 0.06). DISCUSSION: Physiological (deltaRMR-24 hours) and behavioral factors (previous frequency of dieting and hunger score) predicted failure of weight maintenance and, as such, can be used to identify women who are at risk for weight regain.     

Energy expenditure in African American and white boys and girls in a 2-y follow-up of the Baton Rouge Children's Study

BACKGROUND: Previously reported race and sex differences in energy expenditure (EE) may play a role in body fat gain. OBJECTIVE: The purpose of the study was to determine the relations between race, sex, Tanner stage, and EE. DESIGN: We conducted a 2-y follow-up study of EE in 114 African American (AA) and white girls and boys aged 12.7 +/- 0.1 y ( +/- SE), who were stratified as obese or lean and were part of the Baton Rouge Children's Study. Total daily EE (TDEE) was measured by using doubly labeled water. Resting metabolic rate (RMR) and thermic effect of food were measured by using indirect calorimetry. RESULTS: White children had significantly higher TDEE and RMR than did AA children when fat-free mass was considered. Boys had significantly higher TDEE and RMR than did girls, even after adjustment for differences in size. TDEE and RMR were significantly higher in obese children, as a result of their greater fat-free mass and body fat, than in lean children. Activity-related EE did not differ significantly between obese and lean children. There was a strong relation between initial and 2-y TDEE and RMR. There was a significant decrease in activity-related EE in both racial groups. AA children had significantly more lean limb mass than did white children. CONCLUSIONS: Average TDEE did not change over 2 y, but RMR increased significantly, and activity-related EE decreased significantly. Differences in trunk and limb lean mass of white and AA children may explain some of the ethnic differences in EE. The decrease in physical activity over 2 y may contribute to the risk of obesity.     

Resting energy expenditure in reduced-obese subjects in the National Weight Control Registry.

BACKGROUND: Weight loss in obese subjects is associated with a reduction in resting metabolic rate (RMR). Whether the reduction can be explained solely by a reduction in lean body mass remains controversial. OBJECTIVE: Our objective was to determine whether the reduction in RMR after weight loss was proportional to the decrease in lean mass alone or was greater than could be explained by body composition. DESIGN: We measured the RMR, fasting respiratory quotient (RQ), and body composition in 40 reduced-obese subjects [ie, 7 men and 33 women who had lost > or = 13.6 kg (30 lb) and maintained the loss for > or = 1 y] enrolled in the National Weight Control Registry and 46 weight-matched control subjects (9 men, 37 women). RESULTS: A stepwise multiple regression found lean mass, fat mass, age, and sex to be the best predictors of RMR in both groups. After adjusting RMR for these variables, we found no significant difference in RMR (5926 +/- 106 and 6015 +/- 104 kJ/d) between the 2 groups (P = 0.35). When we adjusted fasting RQ for percentage body fat and age, the reduced-obese group had a slightly higher (0.807 +/- 0.006) RQ than the control group (0.791 +/- 0.005, P = 0.05). This may have been due to the consumption of a diet lower in fat or to a reduced capacity for fat oxidation in the reduced-obese group. CONCLUSION: These results show that in at least some reduced-obese individuals there does not seem to be a permanent obligatory reduction in RMR beyond the expected reduction for a reduced lean mass.     

Body fat distribution in white and black women: different patterns of intraabdominal and subcutaneous abdominal adipose tissue utilization with weight loss.

BACKGROUND: Intraabdominal adipose tissue (IAAT) is the body fat depot most strongly related to disease risk. Weight reduction is advocated for overweight people to reduce total body fat and IAAT, although little is known about the effect of weight loss on abdominal fat distribution in different races. OBJECTIVE: We compared the effects of diet-induced weight loss on changes in abdominal fat distribution in white and black women. DESIGN: We studied 23 white and 23 black women, similar in age and body composition, in the overweight state [mean body mass index (BMI; in kg/m(2)): 28.8] and the normal-weight state (mean BMI: 24.0) and 38 never-overweight control women (mean BMI: 23.4). We measured total body fat by using a 4-compartment model, trunk fat by using dual-energy X-ray absorptiometry, and cross-sectional areas of IAAT (at the fourth and fifth lumbar vertebrae) and subcutaneous abdominal adipose tissue (SAAT) by using computed tomography. RESULTS: Weight loss was similar in white and black women (13.1 and 12.6 kg, respectively), as were losses of total fat, trunk fat, and waist circumference. However, white women lost more IAAT (P < 0.001) and less SAAT (P < 0.03) than did black women. Fat patterns regressed toward those of their respective control groups. Changes in waist circumference correlated with changes in IAAT in white women (r = 0.54, P < 0.05) but not in black women (r = 0.19, NS). CONCLUSIONS: Despite comparable decreases in total and trunk fat, white women lost more IAAT and less SAAT than did black women. Waist circumference was not a suitable surrogate marker for tracking changes in the visceral fat compartment in black women.     

Do adaptive changes in metabolic rate favor weight regain in weight-reduced individuals? An examination of the set-point theory

BACKGROUND: Obese persons generally regain lost weight, suggesting that adaptive metabolic changes favor return to a preset weight. OBJECTIVE: Our objective was to determine whether adaptive changes in resting metabolic rate (RMR) and thyroid hormones occur in weight-reduced persons, predisposing them to long-term weight gain. DESIGN: Twenty-four overweight, postmenopausal women were studied at a clinical research center in four 10-d study phases: the overweight state (phase 1, energy balance; phase 2, 3350 kJ/d) and after reduction to a normal-weight state (phase 3, 3350 kJ/d; phase 4, energy balance). Weight-reduced women were matched with 24 never-overweight control subjects. After each study phase, assessments included RMR (by indirect calorimetry), body composition (by hydrostatic weighing), serum triiodothyronine (T(3)), and reverse T(3) (rT(3)). Body weight was measured 4 y later, without intervention. RESULTS: Body composition-adjusted RMR and T(3):rT(3) fell during acute (phase 2) and chronic (phase 3) energy restriction (P: < 0.01), but returned to baseline in the normal-weight, energy-balanced state (phase 4; mean weight loss: 12.9 +/- 2.0 kg). RMR among weight-reduced women (4771 +/- 414 kJ/d) was not significantly different from that in control subjects (4955 +/- 414 kJ/d; P: = 0.14), and lower RMR did not predict greater 4-y weight regain (r = 0.27, NS). CONCLUSIONS: Energy restriction produces a transient hypothyroid-hypometabolic state that normalizes on return to energy-balanced conditions. Failure to establish energy balance after weight loss gives the misleading impression that weight-reduced persons are energy conservative and predisposed to weight regain. Our findings do not provide evidence in support of adaptive metabolic changes as an explanation for the tendency of weight-reduced persons to regain weight.     

Body-composition differences between African American and white women: relation to resting energy requirements

BACKGROUND: Body composition differs between African American (AA) and white women, and the resting metabolic rate (RMR) is likely to be lower in AA women than in white women. OBJECTIVE: We tested 2 hypotheses: that AA women have a greater proportion of low-metabolic-rate skeletal muscle (SM) and bone than do white women and that between-race musculoskeletal differences are a function of body weight. DESIGN: Hypothesis 1 was tested by comparing SM, bone, adipose tissue, and high-metabolic-rate residual mass across 22 pairs of matched AA and white women. Magnetic resonance imaging and dual-energy X-ray absorptiometry were used to partition weight into 4 components, and RMR was both calculated from tissue-organ mass and measured. Hypothesis 2 was evaluated by measuring SM, bone, fat, and residual mass in 521 AA and white women with the use of dual-energy X-ray absorptiometry alone. RESULTS: Hypothesis 1: AA women had greater SM ( +/- SD group difference: 1.52 +/- 2.48 kg; P < 0.01) and musculoskeletal mass (1.72 +/- 2.66 kg; P < 0.01) than did white women. RMR calculated from body composition and measured RMR did not differ; RMR estimated by both approaches tended to be lower (approximately 160 kJ/d) in AA women than in white women. Hypothesis 2: SM was significantly correlated with weight, height, age, and race x weight interaction; greater SM in the AA women was a function of body weight. CONCLUSIONS: Lower RMRs in AA women than in white women are related to corresponding differences in the proportions of heat-producing tissues and organs, and these race-related body-composition differences increase as a function of body weight.     

Energy expenditure and free-living physical activity in black and white women: comparison before and after weight loss

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 normal-weight states than did white women and did not compensate with greater physical activity, potentially predisposing them to greater weight regain.     

Changes in regional fat redistribution and the effects of estrogen during spontaneous weight gain in women with anorexia nervosa

BACKGROUND: Anorexia nervosa is a disease of severe acquired undernutrition with a high and increasing prevalence among young women in the United States. OBJECTIVE: The objective was to investigate the effects of spontaneous outpatient weight recovery and estrogen administration on fat distribution in patients with anorexia nervosa. DESIGN: Twenty-seven amenorrheic women aged 26.6 +/- 1.2 y with anorexia nervosa were identified through an outpatient study of bone loss and were randomly assigned to receive or not receive estrogen without any dietary intervention other than calcium and multivitamin supplements. Body composition was measured at baseline and at 6 and 9 mo and was compared with cross-sectional values obtained in 20 healthy, eumenorrheic, age-matched (25.4 +/- 0.5 y) control subjects. RESULTS: Twenty of the 27 patients with anorexia aged 27.0 +/- 1.3 y spontaneously gained weight (4.1 +/- 0.9 kg); body mass index (in kg/m(2)) increased from 16.1 +/- 0.3 to 17.5 +/- 0.4. Fat mass and lean mass accounted for 68% and 32% of the gain in total body mass, respectively. With spontaneous weight gain, there was a significant increase in the percentage of trunk fat from 32.4 +/- 1.3% at baseline to 36.5 +/- 1.0% at 9 mo (P = 0.03), which correlated with urinary free cortisol (r = 0.66, P = 0.003). Estrogen treatment was not protective against the gain in trunk fat with spontaneous weight gain. CONCLUSIONS: In women with anorexia nervosa, spontaneous weight gain is associated with a significant increase in trunk adiposity, and estrogen administration may not protect against the accumulation of central fat with weight gain.     

Predictors of long-term weight maintenance

OBJECTIVE: The purpose of this study was to evaluate available variables of a long-term weight maintenance study to investigate possible factors predisposing to weight regain after a period of weight loss. RESEARCH METHODS AND PROCEDURES: The Maastricht Weight Maintenance Study is an ongoing longitudinal study of healthy men and women (29 men and 62 women; 18 to 65 years of age; BMI = 30.2 +/- 3.1 kg/m(2)). A variety of parameters were measured before and after a very-low-energy diet and after a follow-up of at least 2 years. RESULTS: Mean weight loss was 7.9 +/- 3.6 kg, and percent weight regain was 113.8 +/- 98.1%. Percent BMI regain was negatively associated with an increase in dietary restraint (r = -0.47, p < 0.05). Percent weight regain was negatively correlated with baseline resting metabolic rate (r = -0.38, p = 0.01) and baseline fat mass (r = -0.24, p = 0.05) and positively correlated with the magnitude of change in body weight (BW) expressed as maximum amplitude of BW (r = 0.21, p < 0.05). In addition, amplitude of BW was positively correlated with the frequency of dieting (r = 0.57, p < 0.01). DISCUSSION: The best predictors for weight maintenance after weight loss were an increase in dietary restraint during weight loss, a high baseline resting metabolic rate, a relatively high baseline fat mass favoring a fat-free mass-sparing effect during weight loss, a rather stable BW, and a low frequency of dieting. Therefore, BW maintenance after BW loss seems to be a multifactorial issue, including mechanisms that regulate an individuals' energy expenditure, body composition, and eating behavior in such a way that energy homeostasis is maintained.     

Differences in resting metabolic rate between white and African-American young adults

OBJECTIVE: A reported lower resting metabolic rate (RMR) in African-American women than in white women could explain the higher prevalence of obesity in the former group. Little information is available on RMR in African-American men. RESEARCH METHODS AND PROCEDURES: We assessed RMR by indirect calorimetry and body composition by DXA in 395 adults ages 28 to 40 years (100 African-American men, 95 white men, 94 African-American women, and 106 white women), recruited from participants in the Coronary Artery Risk Development in Young Adults (CARDIA), Birmingham, Alabama, and Oakland, California, field centers. RESULTS: Using linear models, fat-free mass, fat mass, visceral fat, and age were significantly related to RMR, but the usual level of physical activity was not. After adjustment for these variables, mean RMR was significantly higher in whites (1665.07 +/- 10.78 kcal/d) than in African Americans (1585.05 +/- 11.02 kcal/d) by 80 +/- 16 kcal/d (p < 0.0001). The ethnic x gender interaction was not significant (p = 0.9512), indicating that the difference in RMR between African-American and white subjects was similar for men and women. DISCUSSION: RMR is approximately 5% higher in white than in African-American participants in CARDIA. The difference was the same for men and women and for lean and obese individuals. The prevalence of obesity is not higher in African-American men than in white men. Because of these reasons, we believe that RMR differences are unlikely to be a primary explanation for why African-American women are more prone to obesity than white women.     

Energy requirements in the eighth decade of life

BACKGROUND: Knowledge of energy requirements among relatively healthy elderly is limited. OBJECTIVES: The objectives of the study were to measure total energy expenditure (TEE)-derived energy requirements in a biracial population of older adults without limitations to daily life and to test these empirical measures against national and international recommendations. DESIGN: TEE (measured by the doubly labeled water method), resting metabolic rate (RMR), activity-related energy expenditure (AEE), and body composition were measured in 288 persons aged 70-79 y selected from the Health, Aging, and Body Composition Study. RESULTS: TEE was lower in women (approximately 530 kcal/d; P < 0.0001) than in men because of the women's lower RMR and AEE. Fat-free mass explained the sex difference in RMR, but body weight failed to account for the women's lower AEE (approximately 1 kcal x kg(-1) x d(-1); P = 0.007). Blacks had lower TEE than did whites (approximately 100 kcal/d, P = 0.03), and that was explained by blacks' lower RMR. Physical activity level (TEE/RMR) did not differ significantly between sexes and races (1.70 +/- 0.23). The World Health Organization (WHO) recommendations overestimated TEE by 10 +/- 15% (P < 0.0001) in women but not in men, and the dietary reference intakes (DRIs) were accurate to 0 +/- 14% (P = 0.1). Both WHO and DRI recommendations are based on an underestimated physical activity level, and WHO recommendations are based on overestimated RMR. CONCLUSIONS: This study of well-functioning older adults confirms the racial difference in energy metabolism and supports the use of the 2002 DRIs. Because the DRIs and WHO recommendations underestimated PAL, new predictive equations of energy requirements are proposed.     

Is resting metabolic rate different between men and women?

A low resting metabolic rate (RMR) has been proposed as a possible cause for the increased body fat commonly seen in women compared with men. Absolute RMR is higher in men, but whether RMR adjusted for lean body mass (LBM) remains higher is unresolved. The objective of the present study was to determine whether RMR adjusted for various body composition factors differed between healthy adult men and women. Thirty men years, BMI and twenty-eight women years, BMI were included in the analyses. RMR was measured by open-circuit indirect calorimetry for 60 min. Extracellular water (ECW) was measured by corrected Br(-) space and total body water (TBW) by 2H dilution. LBM was estimated as TBW/0.732. Intracellular water (ICW) was calculated as TBW-ECW, and body cell mass (BCM) as ICW/0.732. Men were heavier and had higher BMI, LBM, BCM and ECW, but less fat mass. Absolute RMR was higher in men than women v. P<0.0001). This difference became non-significant when RMR was adjusted for LBM by ANCOVA v. P=0.2191), but remained significant when adjusted for BCM v. P=0.0249). Fat mass explained a significant amount of variation in RMR in women (r(2) 0.28, P=0.0038), but not in men (r(2) 0.03, P=0.3301). The relationships between body fat and the various subcompartments of BCM and RMR require further elucidation.     

Racial differences in energy expenditure and aerobic fitness in premenopausal women

BACKGROUND: Aerobic fitness, or maximal oxygen uptake (f1.gif" BORDER="0">O(2)max), and energy expenditure (EE) may be lower in African Americans than in whites. OBJECTIVE: The objective of this study was to compare sleeping EE (SEE), resting EE (REE), free-living total EE (TEE), and f1.gif" BORDER="0">O(2)max in African American and white women after adjustment for body composition and free-living activity-related energy expenditure (AEE). DESIGN: Eighteen African American and 17 white premenopausal women were matched for weight, percentage body fat, and age. SEE and REE were measured in a room calorimeter and f1.gif" BORDER="0">O(2)max was measured on a treadmill. Fat-free mass (FFM) and fat mass (FM) (4-compartment model), AEE (doubly labeled water and SEE), and regional lean tissue (dual-energy X-ray absorptiometry) were used as adjustment variables in SEE, REE, TEE, and f1.gif" BORDER="0">O(2)max comparisons. RESULTS: The African American women had significantly more limb lean tissue and significantly less trunk lean tissue than did the white women. The African American women also had significantly lower SEE (6.9%), REE (7.5%), TEE (9.6%), and f1.gif" BORDER="0">O(2)max (13.4%) than did the white women. Racial differences persisted after adjustment for f1.gif" BORDER="0">O(2)max, AEE, FFM, and limb lean tissue but disappeared after adjustment for trunk lean tissue. The f1.gif" BORDER="0">O(2)max difference was independent of all body-composition variables and of AEE. CONCLUSIONS: African American women had lower aerobic fitness than did white women, independent of differences in lean tissue or AEE. Diminished racial differences in SEE, REE, and TEE after adjustment for trunk lean tissue suggest that low EE in African American women is mediated by low volumes of metabolically active organ mass.     

Long-term changes in energy expenditure and body composition after massive weight loss induced by gastric bypass surgery

BACKGROUND: Little is known about the determinants of individual variability in body weight and fat loss after gastric bypass surgery or about the effects of massive weight loss induced by this surgery on energy requirements. OBJECTIVES: The objectives were to determine changes in energy expenditure and body composition with weight loss induced by gastric bypass surgery and to identify presurgery predictors of weight loss. DESIGN: Thirty extremely obese women and men with a mean (+/- SD) age of 39.0 +/- 9.6 y and a body mass index (BMI; in kg/m(2)) of 50.1 +/- 9.3 were tested longitudinally under weight-stable conditions before surgery and after weight loss and stabilization (14 +/- 2 mo). Total energy expenditure (TEE), resting energy expenditure (REE), body composition, and fasting leptin were measured. RESULTS: Subjects lost 53.2 +/- 22.2 kg body weight and had significant decreases in REE (-2.4 +/- 1.0 MJ/d; P < 0.001) and TEE (-3.6 +/- 2.5 MJ/d; P < 0.001). Changes in REE were predicted by changes in fat-free mass and fat mass. The average physical activity level (TEE/REE) was 1.61 at both baseline and follow-up (P = 0.98). Weight loss was predicted by baseline fat mass and BMI but not by any energy expenditure variable or leptin. Measured REE at follow-up was not significantly different from predicted REE. CONCLUSIONS: TEE and REE decreased by 25% on average after massive weight loss induced by gastric bypass surgery. REE changes were predicted by loss of body tissue; thus, there was no significant long-term change in energy efficiency that would independently promote weight regain.     

Energy restriction results in a mass-adjusted decrease in energy expenditure in cats that is maintained after weight regain

Dietary energy restriction (ER) is used to treat obesity in cats but it is often unsuccessful. The purpose of this study was to determine whether ER results in a sustained decrease in mass-adjusted energy expenditure (EE) that may oppose weight loss and promote weight regain. EE and body composition were measured in 10 adult neutered cats at 3 time points: baseline (obese cats), during weight loss (40% ER), and following weight regain. The cats started with a body weight (BW) of 6.1 +/- 0.30 kg, body condition score (BCS) of 7.6 +/- 0.14 (on a 9-point scale), and fat body mass (FM) of 38 +/- 1.0% of BW. After weight loss, BW was 5.0 +/- 0.19 kg, BCS was 5.5 +/- 0.07 kg, and FM was 31 +/- 1.6% (P < 0.01). After weight regain, BW was 6.2 +/- 0.30 kg, BCS was 7.7 +/- 0.16, and FM was 42 +/- 1.8% (P < 0.01). Total EE decreased from 1258 +/- 33.7 kJ/d to 1025 +/- 39.6 kJ/d during weight loss (P < 0.001). After weight regain, EE was still lower than baseline (1103 +/- 41.5 kJ/d, P < 0.001). Energy intake (EI) at baseline (1337 +/- 50.6 kJ/d) was higher than EI after weight loss and regain (1217 +/- 61.2 kJ/d), resulting in no differences in energy balance (78 +/- 30.4 and 104 +/- 35.4 kJ/d, respectively, P = 0.581). These results support the hypothesis that ER results in a mass-adjusted decrease in EE in cats that is maintained after weight regain.     

Effects of protein-rich supplementation and nandrolone in lean elderly women with femoral neck fractures

AIM: To evaluate the effects of a protein-rich liquid supplementation, alone or in combination with the anabolic steroid nandrolone decanoate, on body composition, activities of daily living (ADL) status and the health-related quality of life (HRQoL) after a femoral neck fracture. METHODS: Sixty women, aged 83 +/- 5 years (mean +/- SD), BMI < 24 kg/m2 (20.4 +/- 2 kg/m2 ) and capable of co-operating, with a femoral neck fracture treated with internal fixation, were randomised to open treatment during 6 months with a protein-rich liquid formula alone (PR, Fortimel, 200 ml/day, 20 g protein/day) or in combination with nandrolone decanoate (PR/N, Deca-Durabol 25 mg i.m./3 weeks) or to a control group (C). The patients were re-examined after 6 and 12 months regarding body weight (BW), lean body mass (LBM, DXA), ADL status according to Katz, HRQoL according to EQ 5-D and fracture healing. RESULTS: LBM decreased in the C (-1.2 +/- 2 kg) and PR groups (-1.2 +/- 1 kg) but remained the same in the PR/N group (0.3 +/- 1 kg) (P < 0.05 between groups). ADL remained at a high level in the two intervention groups but declined significantly in the C group (P < 0.005 between groups). The decline in HRQoL was least pronounced in the PR/N group at 6 months (P < 0.05 between groups). Patients with fracture healing complications lost more BW (P < 0.05) and LBM (P < 0.01) than patients with uneventful fracture healing. CONCLUSION: Protein-rich liquid supplementation in combination with nandrolone given for 6 months to lean elderly women after a femoral neck fracture may positively affect LBM, ADL and HRQoL.     

Comparison of energy-restricted very low-carbohydrate and low-fat diets on weight loss and body composition in overweight men and women

OBJECTIVE: To compare the effects of isocaloric, energy-restricted very low-carbohydrate ketogenic (VLCK) and low-fat (LF) diets on weight loss, body composition, trunk fat mass, and resting energy expenditure (REE) in overweight/obese men and women. DESIGN: Randomized, balanced, two diet period clinical intervention study. Subjects were prescribed two energy-restricted (-500 kcal/day) diets: a VLCK diet with a goal to decrease carbohydrate levels below 10% of energy and induce ketosis and a LF diet with a goal similar to national recommendations (%carbohydrate:fat:protein = ~60:25:15%). SUBJECTS: 15 healthy, overweight/obese men (mean +/- s.e.m.: age 33.2 +/- 2.9 y, body mass 109.1 +/- 4.6 kg, body mass index 34.1 +/- 1.1 kg/m2) and 13 premenopausal women (age 34.0 +/- 2.4 y, body mass 76.3 +/- 3.6 kg, body mass index 29.6 +/- 1.1 kg/m2). MEASUREMENTS: Weight loss, body composition, trunk fat (by dual-energy X-ray absorptiometry), and resting energy expenditure (REE) were determined at baseline and after each diet intervention. Data were analyzed for between group differences considering the first diet phase only and within group differences considering the response to both diets within each person. RESULTS: Actual nutrient intakes from food records during the VLCK (%carbohydrate:fat:protein = ~9:63:28%) and the LF (~58:22:20%) were significantly different. Dietary energy was restricted, but was slightly higher during the VLCK (1855 kcal/day) compared to the LF (1562 kcal/day) diet for men. Both between and within group comparisons revealed a distinct advantage of a VLCK over a LF diet for weight loss, total fat loss, and trunk fat loss for men (despite significantly greater energy intake). The majority of women also responded more favorably to the VLCK diet, especially in terms of trunk fat loss. The greater reduction in trunk fat was not merely due to the greater total fat loss, because the ratio of trunk fat/total fat was also significantly reduced during the VLCK diet in men and women. Absolute REE (kcal/day) was decreased with both diets as expected, but REE expressed relative to body mass (kcal/kg), was better maintained on the VLCK diet for men only. Individual responses clearly show the majority of men and women experience greater weight and fat loss on a VLCK than a LF diet. CONCLUSION: This study shows a clear benefit of a VLCK over LF diet for short-term body weight and fat loss, especially in men. A preferential loss of fat in the trunk region with a VLCK diet is novel and potentially clinically significant but requires further validation. These data provide additional support for the concept of metabolic advantage with diets representing extremes in macronutrient distribution.     

Regional changes in body composition by time of year in healthy postmenopausal women.

We examined regional changes in fat, lean, and bone tissue for greater than 1 y in 125 postmenopausal women. Duplicate whole-body scans were performed at 6-mo intervals. Period 1 was June or July to December or January and period 2 was December or January to the following June or July. Lean and bone tissue mass in the arms, legs, trunk, and whole body increased in period 1 and decreased in period 2 [eg, lean tissue in legs increased 1.84 +/- 0.41% (mean +/- SE) in period 1 and decreased 2.84 +/- 0.39% in period 2, P less than 0.001]. In each region except the arms, fat tissue decreased in period 1 and increased in period 2. Quadriceps muscle strength was correlated with lean tissue mass of the legs [rp (controlled for height) = 0.24, P V 0.02] and physical activity was correlated with quadriceps strength. Overall, body weight did not change significantly (0.17 +/- 0.41% increase, P greater than 0.20); however, there was a net loss of 1.08 +/- 0.39% (P less than 0.01) in lean tissue in the legs and a net increase of 3.43 +/- 1.12% (P less than 0.01) in fat tissue in the trunk.