The relationship between body fat distribution and weight loss in obese adolescent girls.

Recent studies have demonstrated an association between the pattern of body fat distribution and the occurrence of cardiovascular risk factors. In this study, we evaluated changes in body fat distribution as defined by several anthropometric criteria during a six week weight reduction programme in 110 obese adolescent girls (mean age 15.2 +/- 0.4 years). The standardized regimen included a mixed diet of 1032 kcal/day and a daily exercise programme of 1-2 h duration. The mean weight loss was 8.6 +/- 2.8 kg, decreasing the body mass index (BMI) from 31.4 +/- 4.7 to 28.2 +/- 4.9 kg/m2 (P < 0.01). The reduction in body weight was accompanied by a significant decrease in the waist-to-hip ratio (WHR) from 0.86 +/- 0.06 to 0.81 +/- 0.05 (P < 0.01). The initial WHR was correlated with the degree of weight loss independent of the initial weight (r = 0.34, P < 0.001). Categorized according to the waist-to-hip ratio girls in the upper tertile (WHR > 0.88) lost significantly more weight than girls in the lower tertile (WHR < 0.80) (9.8 +/- 2.7 vs. 6.8 +/- 2.5 kg, P < 0.01). These findings suggest that girls with an abdominal type of obesity benefit more from a weight reduction programme than girls with a gluteal-femoral type of obesity.     

Continuous infusion of furosemide versus intermittent boluses in acute decompensated heart failure: Effect on thoracic fluid content

Introduction

The administration of loop diuretics in the management of acute decompensated heart failure (ADHF) whether IV boluses or continuous infusion is still controversial. We intended to evaluate differences between the two administration routes on the thoracic fluid content (TFC) and the renal functions.

Effect of weight loss on resting energy expenditure in obese prepubertal children.

To assess the effect of weight loss on resting metabolic rate (RMR), the energy expenditure of eight obese prepubertal children (age 9 +/- 1 years; weight 48.7 +/- 9.1 kg; BMI 25.3 +/- 3.9) and of 14 age-matched children of normal body weight (age 9 +/- 1 years; weight 28.8 +/- 5.6 kg; BMI 16.5 +/- 1.7) was measured by indirect calorimetry. The obese children were reinvestigated after a mean weight loss of 5.4 +/- 1.2 kg induced by a six-months mixed hypocaloric diet. Before slimming, the obese group showed a higher daily energy intake than the control group (10.40 +/- 3.45 MJ/day vs 7.97 +/- 2.02 MJ/day respectively; P less than 0.05) but a similar value was observed per unit fat-free mass (FFM) (0.315 +/- 0.032 MJ/kgFFM/day vs 0.329 +/- 0.041 MJ/kgFFM/day respectively). The average RMR of the obese children was greater than that of the control group (5217 +/- 531 kJ/day vs 4477 +/- 506 kJ/day) but similar after adjusting for FFM (4728 +/- 3102 kJ/day vs 4899 +/- 3102 kJ/day). Weight loss resulted in a reduction in RMR (5217 +/- 531 kJ/day vs 4874 +/- 820 kJ/day), each kg of weight loss being accompanied by a decrease of RMR of 64 kJ (15.3 kcal) per day. The changes in RMR induced by weight loss paralleled the changes in FFM. No difference was found in average RQ in obese children vs controls (0.85 +/- 0.03 vs 0.87 +/- 0.03 respectively) and in the obese children before and after weight loss (0.87 +/- 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)     

Pregnancy, weight cycling and weight gain in obesity.

Pregnancy constitutes a biological cause of weight cycling. Since repeated weight variation has been associated with sustained weight increase and subsequent metabolic complications, the role of pregnancy in affecting body weight was analysed retrospectively in a group of 128 severely obese patients at the obesity unit. Their present mean age was 47.8 +/- 10.7 years, the mean age at birth of their first child 24.1 +/- 5.1 years and their mean present BMI was 37.8 +/- 5.5 kg/m2 (s.d.). Seventy-three percent of the women reported a weight retention of more than 10 kg one year after delivery. The median number of other weight cycling events was seven. Such cycling did not correlate to present BMI or weight increase during any pregnancy. Weight increases during subsequent pregnancies were not correlated to each other. The results support the hypothesis that for women who develop severe obesity, their pregnancy-related weight increases contribute substantially to their body weight development.     

Substantial weight gain during adulthood: the road to bariatric surgery

We sought to examine the relationship of body mass index (BMI) at age 18 years with the degree and rate of rise in body weight during adulthood among the morbidly obese. We evaluated 196 patients with a standard medical history form and a structured interview with questions regarding weight at age 18 years. The study included 40 (20.4%) men and 156 (79.6%) women. The mean BMI was 50.2+/-8.0 kg/m2, range 37.0-80.0 kg/m2. Based on self-reported weight, 133 (67.9%) were overweight/obese (BMI >25 kg/m2) and 68 (34.7%) were obese (BMI > or =30 kg/m2) at age 18 years. The distribution of cumulative weight gain was normal with a mean of 60.8+/-23.7 kg. There was a positive relationship (r=0.36, p<0.0001) between BMI at age 18 years and BMI in adulthood at a mean of 44+/-10.6 years. Independent predictors for cumulative adult weight gain were BMI at age 18 years (p<0.0001); women (p<0.0001); African Americans (p=0.05). These data suggest that modestly overweight young adults can have excessive weight gains during adult life, resulting in morbid obesity and high rates of obesity-related comorbidities.     

Modest weight loss improves insulin action in obese African Americans

OBJECTIVE: We have previously shown that short-term energy restriction followed by modest lifestyle changes improves glucose tolerance for up to 1 year in obese individuals. The purpose of the present study was to determine the mechanism by which improvements in glucose tolerance occur in obese African Americans with insulin resistance and abnormal glucose tolerance. RESEARCH DESIGN AND METHODS: Nine subjects (53 +/- 2 years; body mass index, 37 +/- 3 kg/m 2 [mean +/- SEM]) received a low-energy diet (3883 +/- 222 kJ/d) for 1 week, and then followed a modest lifestyle intervention program for up to 1 year. Body composition was estimated by hydrostatic weighing, and insulin secretion and action were assessed during a hyperglycemic clamp with superimposed arginine infusion and fat meal. Baseline and final tests were performed during weight stability. RESULTS: Significant improvements ( P < .05) were observed for body weight (-6.1 +/- 1.1 kg), body composition (-5.5 +/- 1.3 kg fat mass), fasting plasma glucose (-1.1 +/- 0.3 mmol/L), fasting insulin (-52 +/- 21 pmol/L), oral glucose tolerance, and insulin action (+24%), defined as an increase in glucose disposal rate relative to plasma insulin concentration during the hyperglycemic clamp. These improvements were independent of an acute effect of energy restriction or weight loss, because body weight was stable. CONCLUSIONS: These results suggest that the improvements in glucose tolerance with a modest lifestyle intervention were attributable to an improvement in insulin action, and provide evidence that despite persistent obesity (body mass index, 34.7 +/- 2.4 kg/m 2 ), long-term benefits can be achieved with relatively small weight loss in obese African Americans.     

Differentiated long-term effects of intentional weight loss on diabetes and hypertension

The beneficial effects of weight loss in the obese have been widely accepted. Still, there is a lack of controlled studies displaying large maintained weight losses over long periods (>4 years). We wanted to examine the results of long-standing intentional weight loss on the development of diabetes and hypertension in severely obese individuals over an 8-year period. In the ongoing prospective Swedish Obese Subjects (SOS) study, 346 patients awaiting gastric surgery were matched with 346 obese control subjects on 18 variables by a computerized matching program. The controls were drawn from a registry consisting of 1508 obese potential controls examined at primary health care centers in Sweden. Of the 692 selected patients (body mass index 41.2+/-4.7 kg/m(2) [mean+/-SD]), 483 (70%) were followed for 8 years. No significant weight changes occurred in the obese control group over 8 years. Gastric surgery resulted in a maximum weight loss of -31.1+/-13.6 kg after 1 year. After 8 years, the maintained weight loss was still 20.1+/-15.7 kg (16.3+/-12.3%). Whereas this weight reduction had a dramatic effect on the 8-year incidence of diabetes (odds ratio 0.16, 95% CI 0.07 to 0.36), it had no effect on the 8-year incidence of hypertension (odds ratio 1.01, 95% CI 0.61 to 1.67). A differentiated risk factor response was identified: a maintained weight reduction of 16% strongly counteracted the development of diabetes over 8 years but showed no long-term effect on the incidence of hypertension.     

Effect of serotonin re-uptake inhibition by fluoxetine on body weight and spontaneous food choice in obesity.

The effect of fluoxetine on body weight and spontaneous food choice was studied in twenty-three healthy, non-depressed, obese females on an outpatient basis. After a one week placebo run-in period, subjects were randomized to receive either fluoxetine (FXT) 60 mg daily (n = 11) or placebo (P) (n = 12) for 6 weeks in a double blind study design. BMI (35.2 +/- 0.8 vs 36.4 +/- 1.3 kg/m2, mean +/- s.e.m.) and age (38.1 +/- 239 vs 37.3 +/- 2.7 years) were not different in either group. No specific diet was prescribed. On four separate days per 14 days food records were collected. Data were analysed with the use of food composition tables. Statistical analysis was performed using Student's t test for independent samples for data on body weight and calorie intake. Macro-nutrient composition of the diet was analysed using multivariate analysis of variance and post hoc Student's t test for independent samples. All subjects lost weight during fluoxetine treatment. Mean (+/- s.e.m.) weight loss in the fluoxetine treated group was 3.6 +/- 0.5 kg, compared to a mean weight gain of 0.3 +/- 0.5 kg in the placebo treated group (P less than 0.001). In all patients food intake was reduced during fluoxetine treatment and this reduction could fully account for the observed weight loss. The mean total caloric intake per day was significantly lower during fluoxetine treatment compared with placebo (FXT 1123 +/- 118 kcal vs P 1845 +/- 87 kcal, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)     

Does ephedrine promote weight loss in low-energy-adapted obese women?

A double-blind cross-over randomized study was performed in 10 selected adult overweight and obese (body mass index greater than 27) women who had been adapted to low-energy intake for a long period of time and who had shown difficulty in losing weight with conventional hypocaloric treatment. Combined with diet therapy (1000-1400 kcal/day), l(-)ephedrine hydrochloride (50 mg three times a day per os) or placebo were administered daily before each meal, after a period of stabilization with diet only for 1 month. Each pharmacological treatment lasted for 2 months. Weight loss was significantly (P less than 0.05) greater during the ephedrine period (2.41 +/- 0.61 kg) than during the placebo period (0.64 +/- 0.50 kg). None of the patients presented clinically important side-effects. These preliminary results seem to suggest a possible role for a thermogenic compound such as ephedrine in promoting weight loss in low-energy-adapted obese women.     

The effect of orlistat-induced weight loss on interleukin-6 and C-reactive protein levels in obese subjects

OBJECTIVE: Inflammation plays a major role in the pathogenesis of atherosclerosis. Obesity is an independent risk factor for cardiovascular disease, which may be mediated by increased secretion of proinflammatory cytokines by adipose tissue. The aim of this study is to investigate changes in the inflammatory markers interleukin-6 (IL-6) and high-sensitivity C-reactive protein (hs-CRP) during weight reduction with orlistat treatment in obese patients. METHODS AND RESULTS: Thirty-six obese (BMI: 36.1 +/- 3.4 kg/m2) and II non-obese (BMI: 22.9 +/- 1.7 kg/m2) subjects were studied. IL-6 and hs-CRP levels were evaluated at baseline. In obese subjects after treatment of orlistat 120 mg three times daily for 6 months, IL-6 and hs-CRP levels were repeated. Levels of circulating IL-6 (p < 0.05) and hs-CRP (p < 0.01) were significantly higher in the obese group than in the non-obese group. Plasma IL-6 (r = 0.29 and p < 0.05) and CRP (r = 0.35 and p < 0.05) concentrations correlated positively with the level of obesity assessed by BMI at baseline. After 6 months of orlistat treatment in obese subjects, the mean weight of the patients decreased by 6.8 kg, the BMI by 3.2 kg/m2. Compared with baseline, weight loss was associated with significant reductions of IL-6 (p < 0.001) and hs-CRP (p < 0.001) levels. CONCLUSION: In summary plasma IL-6 and hs-CRP levels were increased in obese patients. Orlistat-induced weight reduction was associated with decreasing levels of both IL-6 and hs-CRP in obese subjects. Because inflammatory mediators may be directly involved in atherogenesis, this would suggest that interventions to reduce IL-6 and CRP levels could be cardioprotective.     

Marked weight reduction lowers resting and exercise blood pressure in morbidly obese subjects

Obesity and high blood pressure (BP) often coexist. Weight reduction lowers resting BP but its effect on BP during exercise (a predictor of target organ damage) has not been evaluated. Blood pressure was measured at rest and during cycling, before and after weight reduction induced by gastric restriction. Nineteen subjects (4 male), 41 +/-2 (SEM) years of age and body mass index (BMI) of 43 +/- 0.9 kg/m2, were studied. On each occasion BP was measured at rest, at a steady state of 0 and 25 watts, at peak exercise and 1 min into recovery. Body weight was reduced by 28% +/- 6% and BMI decreased from 43.3 +/- 0.9 to 31.5 +/- 0.7 kg/m2 (P < .01). Both BP and heart rate, at rest and at all exercise intensities, were significantly lower after weight reduction. Resting BP decreased from 133 +/-4/87 +/- 3 mm Hg to 115 +/- 4/77 +/- 2 mm Hg (P < .001), and BP at peak exercise decreased from 181 +/- 8/98 +/- 4 to 162 +/- 6/83 +/- 5 mm Hg (P < .001). The change in resting systolic BP did not correlate with the change in body weight or with the change in heart rate, but it correlated with the baseline systolic BP (R = 0.61; P < .005). It is concluded that marked weight reduction reduces BP at rest and at all exercise intensities. Gastroplasty should be considered as an option in morbidly obese hypertensive patients who are not well controlled with conventional treatment, and who fail to lose or to maintain a reduced weight by calorie restriction alone.     

Recent weight gain in patients with newly diagnosed obstructive sleep apnea.

OBJECTIVE: Patients with obstructive sleep apnea are often obese. Obesity may contribute to both sleep apnea itself and to the cardiovascular risk associated with sleep apnea. Weight loss in obese patients with sleep apnea may alleviate symptoms and decrease the severity of sleep apnea. Whether patients with obstructive sleep apnea are indeed predisposed to recent weight gain, as compared with similarly obese subjects without sleep apnea, is not known. PATIENTS AND METHODS: We compared 1-year weight histories in 53 male and female patients newly diagnosed with obstructive sleep apnea, compared with 24 controls matched for gender, age, body mass index, and percent body fat. Sleep apnea patients had never been treated. Control subjects were proven to be free of sleep-disordered breathing by overnight polysomnography. RESULTS: Patients with obstructive sleep apnea (n = 53) had a significant recent weight gain of 7.4 +/- 1.5 kg compared with a weight loss of 0.5 +/- 1.7 kg (P = 0.001) in similarly obese controls (n = 24). Male patients with obstructive sleep apnea (n = 28) had a history of significant weight gain (6.8 +/- 2.3 kg) over the year preceding the study compared with male control subjects (n = 13), in whom average weight fell by 0.58 +/- 2.4 kg (P = 0.03). Female patients (n = 25) with obstructive sleep apnea had an 8.0 +/- 1.9 kg weight gain compared with female controls (n = 11) who had a history of weight loss of 0.46 +/- 2.6 kg (P = 0.02). CONCLUSION: These findings support the concept that patients with obstructive sleep apnea may be susceptible to increasing obesity in the period preceding the diagnosis of obstructive sleep apnea.     

Associations of leptin, insulin resistance and thyroid function with long-term weight loss in dieting obese men

OBJECTIVE: The aim of the present study was to identify predictors of weight loss in obese men participating in a 2-year behaviour modification programme. DESIGN: Longitudinal, clinical intervention study of a behaviour modifying weight loss program. SETTING: University Hospital, Stockholm, Sweden. SUBJECTS: Forty-four obese men (age, 42.7 +/- 1.1 years: BMI, 37.1 +/- 0.6 kg m(-2), mean +/- SEM) followed for 2 years. INTERVENTIONS: Behaviour modification weight loss programme. MAIN OUTCOME MEASURES: Associations between plasma leptin and thyroid function tests, insulin resistance by homeostatic model assessment (HOMA), dietary recall and anthropometrically determined body composition. RESULTS: At baseline, there were significant correlations between plasma leptin and body mass index (BMI), fat-free mass (FFM) and insulin resistance. Median weight loss over 2 years was 4.9 kg (range, -27.2 to +11.9). Baseline serum leptin concentrations adjusted for BMI (leptin/BMI ratio) were significantly correlated with 2-year weight change (r = 0.34, P = 0.04). A subset of seven of the 44 men gained weight over the 2 years. These 'gainers' differed significantly in initial leptin/BMI ratio (0.62 +/- 0.07) compared with the 37 'losers' (0.42 +/- 0.03, P < 0.05). In a multiple regression model, baseline leptin, insulin and age predicted 22% of the variance in weight change with no additional significant contribution from BMI, FFM, waist:hip ratio, thyroid function tests or energy intake. There was a strong correlation between the change in leptin concentrations and the change in insulin resistance from baseline to 2-year follow-up (r = 0.54; P < 0.001). CONCLUSION: Baseline plasma leptin concentrations predicted long-term weight loss. Inappropriate leptin secretion or disposal, corrected for BMI, was associated with failure to maintain weight loss in obese men in a behaviour modification weight loss programme.     

Body fat distribution and the prognosis for weight reduction: preliminary observations

In a preliminary study the influence of body fat distribution on the degree of weight reduction, blood lipids and blood glucose was investigated in 17 premenopausal obese women (BMI greater than 27 kg/m2), who followed an energy-reduced diet of 4.2 MJ/day for 8 weeks. Body fat distribution was distinguished in an abdominal and gluteal-femoral type using a cut-off point of 0.80 for the ratio of waist-to-hips girth. Mean weight reduction was about 10 kg. Body fat distribution was not related to the ability to lose weight. Body weight reduction was 10.2 +/- 3.3 kg (mean +/- s.d.) in the abdominal obese (n = 8) and 9.6 +/- 2.4 kg in the gluteal-femoral obese women (n = 8). In abdominal obese women, body fat distribution became more intermediate. This change in body fat distribution coincided in the abdominal obese, after weight loss, with greater decreases in blood glucose and serum lipids than in the gluteal-femoral obese.     

Effect of weight reduction on serum ghrelin and TNFalpha concentrations in obese women

Background: Ghrelin causes weight gain by increasing food intake in rodents. Tumor necrosis factor alpha (TNFalpha) is produced by adipose tissue, modulates its metabolism and stimulates catabolic processes. The aim of our study was to evaluate whether weight loss treatment modulates serum concentrations of TNFalpha and ghrelin in obese women. Methods: The study groups included 46 women: 35 obese patients and 11 controls. Serum concentrations of ghrelin and TNFalpha were measured by ELISA before and after a 3-month weight reduction treatment that consisted of a 1000 kcal/day diet and physical exercises. Body composition was determined by impedance analysis using Bodystat. Results: There were no differences in plasma ghrelin concentrations between obese patients and controls. TNFalpha serum levels were higher in obese patients than in controls (p=0.000). The mean weight loss over the 3-month treatment period was 8.7+/-4.5 kg. Following weight loss, serum ghrelin concentration increased significantly (66.3+/-13.7 vs. 73.7+/-14.8 pg/ml; p=0.002) and TNFalpha concentrations decreased significantly (6.9+/-2.6 vs. 5.2+/-1.5 pg/ml; p=0.002). Ghrelin did not show a correlation with weight or percentage of body fat. There was a positive correlation between the increase in ghrelin and the decrease in body fat percentage during weight loss (p=0.002). Conclusion: The increase in serum ghrelin and the decrease in serum TNFalpha, as observed after weight reduction treatment in obese subjects, may constitute a counter-regulatory mechanism preventing further weight loss.     

Effect of weight loss on QTc dispersion in obese subjects.

OBJECTIVE: Increased QTc dispersion is a predictor for ventricular arrhythmias. The aim of this study was to investigate whether QTc dispersion decreases after weight loss program with diet and medical treatment. METHODS: Total 30 (24 women and 6 men, mean age: 44+/-8 years) obese subjects who lost at least 10% of their original weight after 12 week weight loss program were included in present study. Obesity was defined as > or =30 kg/m(2) of body mass index (BMI). Normal weight was defined as < or = 25 kg/m(2) of BMI. RESULTS: After 12 week weight loss program, BMI decreased from 42+/-5 kg/m(2) to 36+/-4 kg/m(2) (p<0.001) and mean weight of obese subjects decreased from 110+/-17 kg to 95+/-15 kg (p<0.001). The mean amount of weight loss was 14.5+/-5.0 kg (range 9-32 kg). The average percent of weight loss was 13% (10.0%-20.3%). Maximum QTc interval (from 446+/-19 ms to 433+/-27 ms, p=0.024) and QTc dispersion (from 66+/-18 ms to 52+/-25 ms, p=0.024) significantly decreased after weight loss program. A statistically significant correlation was found between decrease in level of QTc dispersion and amount of weight loss (r=0.487, p=0.007). CONCLUSION: Substantial weight loss in obese subjects is accompanied by significantly decreased QTc dispersion. The degree of QTc dispersion reduction is associated with amount of weight loss.     

Differential effect of weight loss on insulin resistance in surgically treated obese patients

PURPOSE: To compare the effects of equivalent weight loss induced by two bariatric surgical techniques on insulin action in severely obese patients. METHODS: Eighteen nondiabetic patients with severe obesity (mean [+/- SD] body mass index: 53.5 +/- 9.0 kg/m(2)) and 20 sex- and age-matched lean subjects (body mass index: 23.8 +/- 3.0 kg/m(2)) underwent metabolic studies, including measurement of insulin sensitivity by the insulin clamp technique. Patients then underwent either vertical banded gastroplasty with Roux-en-Y gastric bypass, or biliopancreatic diversion, and were restudied at 5 to 6 months and again at 16 to 24 months postsurgery. RESULTS: At baseline, patients were hyperinsulinemic (194 +/- 47 pmol/L vs. 55 +/- 25 pmol/L, P < 0.0001), hypertriglyceridemic (1.56 +/- 0.30 mmol/L vs. 0.78 +/- 0.32 mmol/L, P < 0.0001), and profoundly insulin resistant (insulin-mediated glucose disposal: 20.8 +/- 4.4 micromol/min/kg fat-free mass vs. 52.0 +/- 10.1 micromol/min/kg, P < 0.0001) as compared with controls. Weight loss by the two procedures was equivalent in both amount (averaging -53 kg) and time course. In the gastric bypass group, insulin sensitivity improved (23.8 +/- 6.0 micromol/min/kg at 5 months and 33.7 +/- 11.3 micromol/min/kg at 16 months, P < 0.01 vs. baseline and controls). In contrast, in the biliopancreatic diversion group, insulin sensitivity was normalized already at 6 months (52.5 +/- 12.4 micromol/min/kg, P = 0.72 vs. controls) and increased further at 24 months (68.7 +/- 9.5 micromol/min/kg, P < 0.01 vs. controls) despite a persistent obese phenotype (body mass index: 33.2 +/- 8.0 kg/m(2)). CONCLUSION: In surgically treated obese patients, insulin sensitivity improves in proportion to weight loss with use of predominantly restrictive procedures (gastric bypass), but is reversed completely by predominantly malabsorptive approaches (biliopancreatic diversion) long before normalization of body weight. Selective nutrient absorption and gut hormones may interact with one another in the genesis of the metabolic abnormalities of obesity.     

Maintenance of resting energy expenditure after weight loss in premenopausal women: potential benefits of a high-protein, reduced-calorie diet

The number of contemporary diet plans promoting high protein intakes for weight management has increased dramatically. Complementing this dietary approach with increased physical activity has proven to be beneficial. Recent studies have suggested that protein intakes in excess of the current Recommended Dietary Allowance (0.8 g/kg) may be of metabolic benefit during weight loss. This investigation assessed changes in resting energy expenditure and substrate oxidation in overweight and obese premenopausal women in response to a weight loss intervention that combined a high-protein, reduced-calorie diet with increased physical activity. Thirty-nine overweight and obese premenopausal women (age, 30.9 +/- 1.5 years; body mass index, 30.2 +/- 0.5 kg/m2) participated in a 10-week weight loss program in which they ate a reduced-calorie diet for which protein provided 30% of total energy and approximated 1.4 g/kg. Subjects incrementally increased physical activity (ie, steps walking) throughout the diet intervention period. Resting energy expenditure, substrate oxidation, and body composition were assessed before (PRE) and after (POST) the 10-week weight loss program. Subjects experienced a 5% decrease in body weight, with significant decreases in both fat mass (PRE, 35.5 +/- 1.2 kg; POST, 32.4 +/- 1.1 kg; P < .0001) and fat-free mass (PRE, 44.6 +/- 0.7 kg; POST, 43.6 +/- 0.7 kg; P < .0001). Changes in body weight or body composition did not alter resting energy expenditure. Protein oxidation increased (PRE, 18% +/- 1%; POST, 20% +/- 1%; P < .05) and fat oxidation decreased (PRE, 37% +/- 3%; POST, 30% +/- 3%; P < .05) after the 10-week intervention. These findings illustrate that a weight loss intervention combining consumption of a high-protein, reduced-calorie diet with increased physical activity promotes weight loss without negatively impacting resting energy expenditure in this population of women.     

Reproducibility of fasting plasma leptin concentration in lean and obese humans

We determined the reproducibility of plasma leptin levels in 20 healthy subjects (10 men, 10 women; 10 lean, 10 obese) at stable body weight. Blood samples were obtained, after an overnight fast, between 0700 and 0800 on days 1, 2, 3, 4, 5, 12, 19, and 26. Body weights were recorded on the same days. Plasma leptin was measured using a specific radioimmunoassay. The mean +/- SE baseline body weights (kg) were 65.8 +/- 3.6 (lean) and 96.4 +/- 7.1 (obese). The body mass indices (BMI) were 22.9 +/- 2.8 kg/m2 (lean) and 32.7 +/- 2.2 kg/m2 (obese). The mean daily fasting plasma glucose level was 98.7 +/- 3.7 mg/dl. Baseline plasma leptin levels (ng/ml) were 5.3 +/- 0.75 in lean men, 14.9 +/- 4.6 in obese men, 11.2 +/- 2.8 in lean women, and 27.1 +/- 8.4 in obese women. Fasting leptin levels on days 2 to 26 were highly correlated with the baseline levels on day 1 (r2 = 0.9, P<0.0001). Body weights remained within 98%-102% of baseline, whereas intra-individual leptin levels fluctuated between 80% and 120% of baseline values, throughout the 26 days of study. We conclude that fasting plasma leptin levels are reproducible, with a maximum day-to-day variation of approximately 20%, in healthy, free-living, lean and obese persons who maintain a stable body weight.