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Weight reduction is associated with a decrease in the risk of developing cardiovascular disease. We hypothesized that, given the central role of reactive oxygen and nitrogen species in vascular biology, changes in nitric oxide (NO) metabolism contribute to benefits of weight loss. In a controlled weight loss trial involving overweight (body mass index (BMI) = 27-30 kg/m(2)), otherwise healthy premenopausal Caucasian and African-American women, serum levels of nitrite and nitrate, as an index of NO production, and protein 3-nitrotyrosine and myeloperoxidase (MPO), as markers of inflammation, were determined. Testing was performed before and after reduction to normal body weight (BMI < 25) under standardized conditions, with controlled diet, and following 1 month of weight maintenance. After weight loss there was an increase in nitrite and nitrate, and levels were higher among African-American women relative to Caucasian counterparts. Whereas weight loss was associated with a decrease in 3-nitrotyrosine in Caucasian women, no change was observed among African-Americans. Furthermore, MPO levels increased in response to weight loss for African-Americans, but did not change in Caucasian women. These data indicate that vascular production of reactive nitrogen species can be modulated by race and weight loss and highlight important racial differences in these responses and are discussed in the context of risk for developing vascular disease.

Background: Little is known about the effect of weight change on regional lean body mass (LBM) distribution or on racial differences in resting metabolic rate (RMR)., Objective: The study compared total and regional LBM patterns in white and black women after weight loss and regain and assessed the influence of regional LBM on variances in RMR., Design: Eighteen white and 22 black women who did not differ in age, weight, and height were studied 3 times: in the overweight state, after weight reduction to the normal-weight state, and after 1 y without intervention. Total and regional lean and fat masses were assessed by dual-energy X-ray absorptiometry., Results: White and black women did not differ significantly in mean (+/- SD) weight loss (13.4 +/- 3.6 and 12.7 +/- 3.2 kg, respectively) and regain (6.1 +/- 5.5 and 6.4 +/- 5.4 kg, respectively). Black subjects had significantly less trunk LBM and significantly more limb LBM at each time point (P < 0.05). In both races, weight regain was associated with significant increases in limb LBM (P < 0.05) but not in trunk LBM (P = 0.21). RMR, adjusted for total LBM and fat mass, was significantly higher in white women after weight loss (P < 0.01) and regain (P < 0.01). However, no racial difference was found when RMR was adjusted for LBM distribution., Conclusions: In both races, trunk LBM decreased with weight loss and remained lower, despite significant weight regain, which potentially reflected decreased organ mass. Regional LBM distribution explained the racial difference in RMR.

Background: Few studies have tested the hypothesis that changes in disease risk factors are more closely associated with changes in visceral fat than with changes in other adipose tissue depots, particularly in subjects with different ethnic or racial backgrounds., Objective: We describe changes in triacylglycerol, total cholesterol, HDL cholesterol, LDL cholesterol, insulin sensitivity (S(i)), visceral fat, and subcutaneous abdominal adipose tissue (SAAT) with weight loss in premenopausal, overweight [body mass index (in kg/m(2)): 27-30], African American (n = 19) and white (n = 18) women., Design: Assessments were performed before and after diet-induced weight loss to a BMI < 25. Body composition and body fat distribution were assessed with dual-energy X-ray absorptiometry and computed tomography, respectively; S(i) was assessed with an intravenous-glucose-tolerance test and minimal modeling., Results: White women lost significantly more visceral fat and less SAAT than did African American women despite similar weight losses (approximately 13 kg). Mixed-model analysis indicated significant effects of time (ie, weight loss) on S(i), triacylglycerol, HDL cholesterol, and LDL cholesterol and of race on triacylglycerol. Time x race interaction terms were not significant. After adjustment for either total body or visceral fat, time was not related to any outcome variable; however, race remained significantly related to triacylglycerol., Conclusions: With weight loss, moderately overweight African American and white women experienced significant improvements in S(i) and lipids. The beneficial effects of weight loss did not differ with race and could not be attributed to a specific body fat depot. Lower triacylglycerol concentrations among African American women are independent of both obesity status and body fat distribution.

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.

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/m2): 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. [ABSTRACT FROM AUTHOR]

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 (T3), and reverse T3 (rT3). Body weight was measured 4 y later, without intervention. Results: Body composition-adjusted RMR and T3:rT3 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. [ABSTRACT FROM AUTHOR]

Compares the free-living energy expenditure and physical activity of black and white women before and after weight loss. Proportion of the decrease in sleeping and resting energy expenditures; Improvement of the physiologic capacity for exercise; Similarity of the free-living physical activities of the two groups of women.

We examined the pattern of weight maintenance in 24 obese women [body mass index (BMI; in kg/m²) 27.6 ± 0.4 who were provided foods for a balanced deficit diet until each had lost ≥ 10 kg and attained normal body weight (BMI 22.9 ± 0.4). At 1 y subjects had regained a mean of 42% of their weight loss, which increased to 87% at 4 y. At 4 y 44% of patients had regained < 75%, whereas 37% had regained ≥ 100% of the weight originally lost. The amount of weight gained was markedly different from that observed in 24 pair-matched never-obese control subjects over the same length of follow-up. Because the results reported herein were obtained without teaching the subjects weight-control skills, they may be regarded as reflective of the natural history of weight maintenance in this population and may serve as a reference for various weight-intervention programs. The pattern of weight rebound observed in this study is very similar to the pattern observed in combined results from published diet and behavioral-modification programs, which raises important questions regarding the efficacy of these approaches in long-term weight maintenance. [ABSTRACT FROM AUTHOR]

On the basis of literature values, the relationship between fat-free mass (FFM), fat mass (FM), and resting energy expenditure [REE (kJ/24 h)} was determined for 213 adults (86 males, 127 females). The objectives were to develop a mathematical model to predict REE based on body composition and to evaluate the contribution of FFM and FM to REE. The following regression equations were derived: 1) REE = 1265 + (93.3 X FFM)(r² = 0.727, P < 0.001); 2) REE = 1114 + (90.4 X FFM) + (13.2 X FM) (R² = 0.743, P < 0.001); and 3) REE = (108 X FFM) + (16.9 X FM) (R² = 0.986, P < 0.001). FM explained only a small part of the variation remaining after FFM was accounted for. The models that include both FFM and FM are useful in examination of the changes in REE that occur with a change in both the FFM and FM. To account for more of the variability in REE, FFM will have to be divided into organ mass and skeletal muscle mass in future analyses. [ABSTRACT FROM AUTHOR]

The separate effects of energy restriction and weight loss on serum lipids were studied in 24 postmenopausal moderately obese women before and after weight loss of > 10 kg to normal weight. Fasting serum triglycerides (TGs), total cholesterol (TC), high-density-lipoprotein (HDL) and low-density-lipoprotein (LDL) cholesterol, and insulin were measured at the end of four 10-d in-hospital phases, two before and two after weight loss: phase I, stable weight; phase II, 3350 kJ/d (800 kcal/d), followed by outpatient weight loss; phase III, 3350 kJ/ d (800 kcal/d); and phase IV, stable weight. Diet composition and exercise were constant the entire study. Energy-restriction effect was determined by comparing average values in stable-weight phases (I and IV) with low-energy phases (II and III); weight-loss effect was determined by comparing values in obese phases (I and II) with reduced-weight phases (III and IV). Energy restriction lowered TG, TC, LDL cholesterol, the LDL-HDL cholesterol ratio, and insulin and raised HDL cholesterol (all P < 0.05). Weight loss lowered TG, TC, LDL cholesterol, and insulin (all P < 0.01) but did not change HDL cholesterol or the LDL-HDL cholesterol ratio. The results suggest that reduction to a weight-steady nonobese state significantly lowers TG, TC. and LDL cholesterol but does not improve HDL cholesterol or the LDL-HDL cholesterol ratio. [ABSTRACT FROM AUTHOR]

It is not known whether the decrease in the thermic effect of food (TEF) in obesity is a consequence of obesity or a factor contributing to the development of obesity. The resting energy expenditure (REE) of 24 obese, nondiabetic, postmenopausal women was 5481 ± 110 kJ/24 h (1310 ± 26.4 kcal/24 h). After weight loss (12.7 ± 0.45 kg) the REE was significantly decreased (4858 ± 94 kJ/24 h, or 1161 ± 22.4 kcal/24 h) and equivalent to the REE of 4866 ± 119 kJ/24 h (1163 ± 28.5 kcal/ 24 h) in 24 never-obese, postmenopausal women. The TEF, expressed as a percentage of the calories ingested, was 8.2 ± 0.50% for obese subjects, 8.7 ± 0.57% for postobese subjects, and 9.8 ± 0.54% for never-obese subjects. Compared with never-obese subjects, the TEF was significantly reduced in obese subjects (P = 0.043) and remained unchanged after weight loss (P = 0.341). These findings indicate that the lower TEF in the obese subjects is uncorrected by weight loss, and thus it is a contributor to obesity rather than a consequence of obesity. [ABSTRACT FROM AUTHOR]

Editorial. Determines a medically safe rate of weight loss based on available data on the risk of gallstone formation during active weight loss. Exponential increase in cholethiasis with increasing weight loss; Potential effects of comorbid conditions; Role of the fat content of the weight-reducing diet in the development of cholethiasis.

Presents information on the the study entitled `Medically Safe Rate of Weight Loss for the Treatment of Obesity: A Guideline Based on Risk of Gallstone Formation.' How the study was conducted; What the study has revealed; Results of study; Conclusion on gallstone formation in obese persons.