Relationship between blood adipocytokines and resting energy expenditure in young and elderly women

It has been demonstrated in a previous study that resting energy expenditure (REE) is associated with adiponectin levels in the blood. However, body composition was not taken into consideration in that study. The purpose of the present study was to again investigate the relationship between blood adipocytokines and REE, adjusted by body composition, in both young and elderly women. REE and blood adipocytokines were measured in 115 young (age: 22.3+/-2.1 y, BMI: 21.3+/-1.9 kg/m(2)) and 71 elderly (63.4+/-6.5 y, 22.9+/- 2.3 kg/m(2)) women. Dual energy X-ray absorptiometry was used to measure percent body fat. Fat mass and fat free mass (FFM) were calculated. REE (kcal/d and kcal/kg BW/d) was lower in elderly women than in young women, but no significant difference was observed in REE, expressed as kcal/kg FFM/d, between the two groups. Although elderly women had a higher percent body fat and higher serum leptin concentrations than young women, plasma adiponectin concentrations did not differ between young and elderly women. In elderly women, REE (kcal/d) was significantly and inversely correlated with plasma adiponectin concentration (r=-0.386, p<0.001), but REE expressed per kilogram of BW or FFM was not significantly correlated. Furthermore, no significant correlation was observed between REE (kcal/d) and concentrations of plasma adiponectin or serum leptin, after adjusting for potential confounders such as body composition and hormones, in either age group. These results suggest that adipocytokines do not influence REE in adult women.     

Energy expenditure before and during energy restriction in obese patients

Twenty-four hour energy expenditure (24 EE), resting metabolic rate (RMR), spontaneous physical activity and body composition were determined in 7 obese patients (5 females, 2 males, 174 +/- 9% IBW, 38 +/- 2% fat mass) on 2 different occasions: before weight reduction, and after 10 to 16 weeks on a hypocaloric diet as outpatients, the recommended energy intake varying from 3500 to 4700 kJ/day depending on the subject. Mean body weight loss was 12.6 +/- 1.9 kg, ie 13% of initial body weight, 72% being fat. Twenty-four hour energy expenditure (24 EE) was measured in a respiration chamber with all the subjects receiving 10418 kJ/d before weight reduction and an average of 3360 +/- 205 kJ/d while on the diet. When expressed in absolute values, both 24 EE and RMR decreased during the hypocaloric diet from 9819 +/- 442 to 8229 +/- 444 and from 7262 +/- 583 to 6591 +/- 547 kJ/d respectively. On the basis of fat-free-mass (FFM), 24 EE decreased from 168 +/- 6 to 148 +/- 5 kJ/kg FFM/d whereas RMR was unchanged (approximately 120 kJ/kg FFM/d). Approximately one half of the 24 EE reduction (1590 kJ/d) was accounted for by a decrease in RMR, the latter being mainly accounted for by a reduction in FFM. Most of the remaining decline in 24 EE can be explained by a decreased thermic effect of food, and by the reduced cost of physical activity mainly due to a lower body weight. Therefore, there seems little reason to evoke additional mechanisms to explain the decline in energy expenditure during dieting.     

The impact of parenteral nutrition on the body composition of patients with acute pancreatitis

BACKGROUND: Nutrition support by the enteral route is now the preferred modality in patients with severe acute pancreatitis. Parenteral nutrition is now required to supplement enteral nutrition when the latter is not able to provide the full nutritional requirement. We report the changes in body composition, plasma proteins, and resting energy expenditure (REE) during 14 days of parenteral nutrition (PN) in patients with acute pancreatitis. METHODS: Total body protein (TBP), total body water (TBW), and total body fat (TBF) were measured by neutron activation analysis and tritium dilution before and after PN. Fat-free mass (FFM) was derived as the difference between body weight and TBF. REE was measured by indirect calorimetry. Protein index (PI) was the ratio of measured TBP to TBP, calculated from healthy volunteers. RESULTS: Fifteen patients with acute pancreatitis (11 men, 4 women; median age 56, range 30-80 years) were studied. Thirteen patients had severe acute pancreatitis (Atlanta criteria), and 1 patient died. The gains in body weight (1.05 +/- 0.77 kg), TBW (0.49 +/- 0.87 kg), TBP (0.20 +/- 0.22 kg), FFM (0.73 +/- 0.92 kg), TBF (0.32 +/- 0.95 kg), and REE (146 +/- 90 kcal/d) after 14 days of PN were not significant. Plasma prealbumin increased by 46.5% (p = .020). When patients (n = 6) with intercurrent sepsis and recent surgery were excluded, there were significant increases in TBP (0.65 +/- 0.17 kg, p = .005) and PI (0.060 +/- 0.011, p = .0006). CONCLUSIONS: Body composition is preserved in acute pancreatitis during 14 days of PN. In patients without sepsis or recent surgery, PN is able to significantly increase body protein stores.     

Influence of methods used in body composition analysis on the prediction of resting energy expenditure

OBJECTIVE: There are considerable differences in published prediction algorithms for resting energy expenditure (REE) based on fat-free mass (FFM). The aim of the study was to investigate the influence of the methodology of body composition analysis on the prediction of REE from FFM. DESIGN: In a cross-sectional design measurements of REE and body composition were performed. SUBJECTS: The study population consisted of 50 men (age 37.1+/-15.1 years, body mass index (BMI) 25.9+/-4.1 kg/m2) and 54 women (age 35.3+/-15.4 years, BMI 25.5+/-4.4 kg/m2). INTERVENTIONS: REE was measured by indirect calorimetry and predicted by either FFM or body weight. Measurement of FFM was performed by methods based on a 2-compartment (2C)-model: skinfold (SF)-measurement, bioelectrical impedance analysis (BIA), Dual X-ray absorptiometry (DXA), air displacement plethysmography (ADP) and deuterium oxide dilution (D2O). A 4-compartment (4C)-model was used as a reference. RESULTS: When compared with the 4C-model, REE prediction from FFM obtained from the 2C methods were not significantly different. Intercepts of the regression equations of REE prediction by FFM differed from 1231 (FFM(ADP)) to 1645 kJ/24 h (FFM(SF)) and the slopes ranged between 100.3 kJ (FFM(SF)) and 108.1 kJ/FFM (kg) (FFM(ADP)). In a normal range of FFM, REE predicted from FFM by different methods showed only small differences. The variance in REE explained by FFM varied from 69% (FFM(BIA)) to 75% (FFM(DXA)) and was only 46% for body weight. CONCLUSION: Differences in slopes and intercepts of the regression lines between REE and FFM depended on the methods used for body composition analysis. However, the differences in prediction of REE are small and do not explain the large differences in the results obtained from published FFM-based REE prediction equations and therefore imply a population- and/or investigator specificity of algorithms for REE prediction.     

No evidence of mass dependency of specific organ metabolic rate in healthy humans

BACKGROUND: In humans, resting energy expenditure (REE) can be calculated from organ and tissue masses using constant specific organ metabolic rates. However, interspecies data suggest allometric relations between body mass and organ metabolic rate with higher specific metabolic rates in mammals with a smaller body mass. OBJECTIVE: The objective was to compare the accuracy of REE prediction with the use of either constant or body mass-dependent specific organ metabolic rates. DESIGN: Healthy subjects (79 women, 75 men) within the normal range of fat mass (FM) expected for a healthy body mass index and aged 18-78 y were stratified into tertiles of body mass. Fifty subjects were grouped as tertile 1 (<66.3 kg), 52 as tertile 2 (> or =66.3 to < or =77.2 kg), and 52 as tertile 3 (>77.2 kg). Magnetic resonance imaging was used to assess the volume of 4 internal organs (brain, heart, liver, and kidneys). REE was measured by indirect calorimetry (REE(m)) and compared with REE calculated from previously published constant (REE(c1)) and body mass-dependent organ metabolic rates (REE(c2)). RESULTS: REE(m) increased significantly with weight tertile (tertile 1: 5536 +/- 529 kJ/d; tertile 2: 6389 +/- 672 kJ/d; tertile 3: 7467 +/- 745 kJ/d; P < 0.01). The deviation REE(m)-REE(c1) did not differ between weight tertiles (tertile 1: 66 +/- 382 kJ/d; tertile 2: 167 +/- 507 kJ/d; tertile 3: 86 +/- 480 kJ/d; NS) and showed no relation with body mass (r = -0.05, NS). By contrast, REE(m)-REE(c2) increased with increasing weight tertile (tertile 1: -45 +/- 369 kJ/d; tertile 2: 150 +/- 503 kJ/d; tertile 3: 193 +/- 482 kJ/d; P < 0.05) and correlated significantly with body mass (r = 0.16, P < 0.05). CONCLUSION: Our data do not support a lower specific organ metabolic rate in humans with a larger body mass than in those with a smaller body mass.     

Negative energy balance in male and female rangers: effects of 7 d of sustained exercise and food deprivation

BACKGROUND: A challenging 7-d ranger field exercise (FEX) by cadets in the Norwegian Military Academy provided a venue in which to study the effects of negative energy balance. OBJECTIVE: We quantified total energy expenditure (TEE), food intake, and changes in body composition in male and female cadets. DESIGN: TEE (measured by doubly labeled water), food intake, activity patterns (measured by accelerometry), and body composition (measured by dual-energy X-ray absorptiometry) were measured in 16 cadets (10 men and 6 women aged 21-27 y). RESULTS: The physically active (approximately 23 h/d) and semistarved (0.2-2.2 MJ/d) cadets lost weight (x +/- SD: men, -7.7 +/- 1.1 kg; women, -5.9 +/- 1.1 kg; P < 0.05). Absolute TEE differed by sex (men, 26.6 +/- 2.0 MJ/d; women, 21.9 +/- 2.0 MJ/d; P < 0.05) but body weight-specific TEE did not (men, 343 +/- 26 kJ . kg(-1) . d(-1); women, 354 +/- 18 kJ . kg(-1) . d(-1); NS). Fat-free mass (FFM) loss differed significantly by sex (men, -4.0 +/- 1.2 kg; women, -2.5 +/- 1.1 kg; P < 0.05), but percentage FFM loss did not (men, -6.3 +/- 1.9%; women, -5.6 +/- 2.4%). In contrast, absolute FM loss did not differ significantly by sex (men, -3.45 +/- 0.72 kg; women, -3.42 +/- 0.22 kg), but fat oxidation (men, 5.2 +/- 1.0 mg . min(-1) . kg FFM(-1); women, 7.3 +/- 0.5 mg . min(-1) . kg FFM(-1)) and the relative contribution of FM to TEE (men, 74 +/- 14%; women, 89 +/- 6%) were significantly greater in women than in men (P < 0.05). CONCLUSION: Female cadets maintained a significantly more fat-predominant fuel metabolism than did male cadets in response to sustained exercise and semistarvation.     

Resting energy expenditure and nutritional state in patients with liver cirrhosis before and after liver transplantation

Resting energy expenditure (REE), body composition, and the biochemical parameters of liver function were measured in 26 patients before and 432 days (range: 103-1022 days) after liver transplantation (LTX). PreLTX REE was variable (mean: 1638 +/- 308 kcal/day, range: 1220-2190 kcal/day or +10 +/- 11% of Harris Benedict = HB prediction, range: -19 - +33%) and was closely related to body cell mass (r = 0.66, p < 0.0003). PostLTX REE was variable (mean: 1612 +/- 358 kcal/day, range: 1010-2490 kcal/day or +5 +/- 15% of HB prediction, range: -20 - +37%) and was closely related to body cell mass (r = 0.65, p < 0.0006). When compared with preLTX values only small changes in mean REE (-71 +/- 43 kcal/day) and a close correlation between pre and postLTX REE (r = 0.82, p < 0.001) were observed. In contrast to REE, changes in body weight were highly variable (-16.5 - +32.7 kg/year). This variance was not explained by the number of postoperative complications, pre and postLTX liver function, possible graft rejection and/or hepatitis reinfection. Pre-operative hypermetabolism (i.e. REE >+20% of HB prediction) was associated with postoperative hypermetabolism and a reduced liver function before and after LTX. Hypermetabolic patients had a poorer nutritional outcome after LTX (weight change: 0 +/- 8.4 kg/year) when compared with normometabolic controls (weight change: +5.7 +/- 7.4 kg/year; p < 0.05). There was no significant association between deviations in pre and postLTX REE and changes in body weight. When corrected for changes in the nutritional state our data provide evidence for the persistence of resting energy expenditure in liver transplant patients.     

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.     

Controlled trial of the metabolic effects of a very-low-calorie diet: short- and long-term effects

Resting energy expenditure (REE), weight, and body composition were measured up to seven times in 13 obese women during a 24-wk study. Patients were randomly assigned to a very-low-calorie diet (VLCD, 500 kcal/d) or a balanced-deficit diet (BDD, 1200 kcal/d). After 8 wk of supplemented fasting, REE of the VLCD patients decreased by 17% whereas that of the BDD patients was virtually unchanged. REE of the VLCD patients increased during 12 subsequent weeks of realimentation such that differences in REE between the two groups were not statistically significant at week 24 (VLCD = -11%, BDD = -2%). Reductions in weight and fat-free mass (FFM) were 12.1% and 3.6% for the VLCD patients and 10.6% and 4.1% for the BDD patients, respectively. There were no significant differences between the groups in pre- to posttreatment changes in REE normalized to FFM. Results suggest that REE recovers partially after consumption of a VLCD. They also provide evidence of a possible metabolic advantage of weight loss by a more moderate restriction.     

Body composition and energy expenditure in Duchenne muscular dystrophy

OBJECTIVE: To investigate the relationship between resting energy expenditure (REE) and body composition in Duchenne Muscular Dystrophy (DMD). DESIGN: An observational study. SETTING: University Research Centre. SUBJECTS: Nine Duchenne children (age range 6-12 y), mean relative weight 128%, agreed to undergo the investigation and all of them completed the study; INTERVENTIONS: Assessment of body composition (total body fat and skeletal muscle mass) by magnetic resonance imaging and resting energy expenditure by indirect calorimetry. MAIN OUTCOME MEASURES: Fat mass (FM; kg and percentage weight), fat-free mass (FFM; kg and percentage weight), muscle mass (kg and percentage weight), resting energy expenditure (kJ/kg body weight and kJ/kg fat-free mass). RESULTS:: In Duchenne children fat mass averages 32% and total skeletal muscle mass 20% of body weight. Resting energy expenditure per kg of body weight falls within the normal range for children of the same age range, while when expressed per kg of FFM is significantly higher than reference values. No relationship was found between REE and total skeletal muscle mass. CONCLUSIONS: Our results do not demonstrate a low REE in DMD boys; on the contrary REE per kg of FFM is higher than normal, probably due to the altered FFM composition. We suggest that the development of obesity in DMD children is not primarily due to a low REE but to other causes such as a reduction in physical activity and or overfeeding.     

Resting energy expenditure is increased in stable, malnourished HIV-infected patients

Resting energy expenditure (REE) was measured by reference to body composition in 50 malnourished patients with human immunodeficiency virus (HIV) infection and compared with that of 14 healthy subjects. Among HIV patients, 40 had acquired immune deficiency syndrome (AIDS) and 10 had AIDS-related complex (ARC). All were in stable condition and had a previous history of progressive wasting, ie, a mean body weight loss of 14.2 +/- 8.1 kg over 16.6 mo (range 2-49 ms). The mean REE was 14% higher than estimated basal energy expenditure (EBEE), according to the Harris and Benedict formula. Thirty-four patients (68%) were classified as hypermetabolic (REE greater than 110% EBEE). The best predictable variable for REE was fat-free mass (FFM), as determined by an anthropometric method (r = 0.72; P less than 0.001). The mean REE was 12% higher in HIV patients than in the control group FFM (156 +/- 19 vs 124 +/- 17 kJ.kg FFM-1.d-1). We concluded that in stable and malnourished HIV patients, the progressive wasting may be partly related to an increase in REE. The mechanism of this hypermetabolic state remains to be established.     

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.     

Energy expenditure in anorexia nervosa: can fat-free mass as measured by bioelectrical impedance predict energy expenditure in hospitalized patients?

Anorexia nervosa (AN) is associated with a reduced metabolically active fat-free mass (FFM) and basal metabolic rate (BMR). Excessive refeeding results in major fat deposition which is not well tolerated by patients. Prediction of BMR is, therefore, a clinical issue during refeeding, but measurement by indirect calorimetry is time-consuming and not widely available. The study aim was to determine if and when BMR could be estimated from prediction formulas based on FFM derived from bioelectrical impedance analysis (BIA) in AN patients during refeeding. Indirect calorimetry and BIA were prospectively measured bi-weekly in 9 AN patients (body mass index 13.7 +/- 0.5 kg/m2) for 10 weeks of refeeding. Initial BMR was 969 +/- 46.7 kcal/d and 27.7 +/- 1.4 kcal/kg FFM, and at week 10 increased to 1360 +/- 44.6 kcal/d and 35.8 +/- 0.8 kcal/kg FFM. While correlations improved with increasing weight, FFM and body mass index, prediction formulas are insufficient to permit prediction of BMR based on weight or FFM, even after 10 weeks of refeeding. To allow for optimal nutritional support, indirect calorimetry measurements may be useful in the early weeks of refeeding because of a large variability of basal metabolic rate between patients.     

Resting energy expenditure in patients with chronic obstructive pulmonary disease

Resting energy expenditure (REE) was measured in 68 patients with stable chronic obstructive pulmonary disease (COPD) and in 34 weight-stable, age-matched (65 +/- 8 y; means +/- SD) healthy control subjects. Fat-free mass (FFM) determined by bioelectrical resistance explained 84% of the variation in REE in the control group but only 34% in the COPD patients. REE could not reliably be predicted from regression equations either developed in healthy subjects or in COPD patients. REE adjusted for FFM was significantly higher (P less than 0.05) in weight-losing (n = 34) than in weight-stable (n = 34) patients (6851 +/- 781 and 6495 +/- 650 kJ/d, respectively). Pulmonary function was more compromised in weight-losing patients. Adjusted REE in weight-stable patients was significantly higher (P less than 0.01) than in the healthy control group (6131 +/- 405 kJ/d). In patients with COPD, factors in addition to FFM are important determinants of REE. A disease-related increase in REE develops, which may contribute to weight loss in COPD in combination with a lack of an adaptive response to undernutrition in weight-losing patients.     

Equation to estimate resting energy expenditure in adolescents with sickle cell anemia

BACKGROUND: Basal energy requirements are higher in adolescents with sickle cell anemia (SCA) than in healthy control subjects. However, no equation is available to accurately predict their energy needs. OBJECTIVE: Our objective was to develop a clinically useful equation to estimate resting energy expenditure (REE) in adolescents with SCA. DESIGN: REE and other components of total energy expenditure were measured in adolescents with SCA (n = 37) and in control subjects (n = 23) for 24 h in a whole-room indirect calorimeter. Multiple linear regression analysis was used to describe the relations of REE with independent variables such as sex, weight, height, fat-free mass, fat mass, age, and hemoglobin concentration in adolescents with SCA. The Bland-Altman comparison technique was used to compare values predicted by existing equations with measured REE values. RESULTS: Mean (+/-SD) measured REEs were 7746 +/- 974 and 6332 +/- 869 kJ/d in the male and female subjects with SCA, respectively, and these values were 16% higher than those in the healthy control subjects. Standard equations underestimated REE by 12% (P 相似文献   

Energy balance in relation to cancer cachexia

The aim of the current study was to determine the contribution of increased resting energy expenditure (REE) and/or decreased energy intake (EI) to the development of weight loss in gastric and colorectal (GCR) and lung cancer patients. REE was measured in 22 GCR cancer patients and 17 lung cancer patients and was compared with REE values in 40 apparently healthy controls. REE in lung cancer patients expressed per kg fat free mass (REE/FFM) was significantly increased when compared to healthy controls (33.5 +/- 5.4 and 29.6 +/- 2.9 kcal, respectively; p < 0.01). GCR cancer patients had no elevated REE compared to these healthy controls. No significant differences in EI were established between the three groups. Eight GCR cancer patients reported a decrease in food intake compared to pre-disease intake, in contrast to only one lung cancer patient. Semi-starving GCR cancer patients showed a significant weight loss (8.7 +/- 8.1%), a low respiratory quoteint (RQ) (0.76 +/- 0.04) and a high beta-hydroxybutyrate level (259 +/- 192 mumol/l), but they showed no difference in REE compared to patients with a normal EI. The current study suggests that weight loss in GCR cancer patients is initiated by decreased food intake, whereas weight loss in lung cancer patients represents a combination of an increased REE and a relatively low EI.     

Resting metabolic rate, fat-free mass and catecholamine excretion during weight loss in female obese patients

The reduction in resting metabolic rate (RMR) during weight loss exceeds that accounted for by changes in body composition by 15%, suggesting that factors other than fat-free mass (FFM) explain the metabolic adaptation during food restriction in obesity. Our study aimed to establish if changes in the sympathoadrenal system activity, as inferred from an integrated measure such as 24 h urinary excretion of catecholamines, may play a role in the RMR adaptation observed during dietary restriction in obese patients. Ninety-three obese female subjects consumed a low-energy diet (LED) (2930 kJ/d (700 kcal/d)) for a 3-week period. At the beginning and at the end of the study, 24 h urinary excretion of catecholamines, FFM and RMR were measured. The LED induced a significant reduction in body weight (-3.3 (SEM 0.4) kg; P < 0.01), FFM (-1.9 (SEM 0.7) kg; P < 0.01) and in the fat mass (-1.2 (SEM 0.5) kg; P < 0.01). Noradrenalin excretion (24 h) decreased during the LED from 264 (SEM 26) during a weight-maintenance period to 171 (SEM 19) nmol/24 h after consumption of the LED for 3 weeks (P < 0.001); mean 24 h adrenalin excretion did not change during the LED (22 (SEM 3) during the weight-maintenance period v. 21 (SEM 3) nmol/24 h after consumption of the LED for 3 weeks; NS). The LED induced a significant decrease in RMR (7300 (SEM 218) v. 6831 (SEM 138) kJ/24 h; P < 0.001). The only independent variable that significantly explained variations in RMR both before and after consumption of the LED for 3 weeks, was FFM (r2 0.79 and r2 0.80 respectively). Urinary noradrenalin excretion explained a further 4% of the variability in RMR, but only before the diet, so that a role of sympathoadrenal system on RMR seems to be present in obese patients in basal conditions but not at the end of the LED.     

Effect of weight reduction on resting energy expenditure, substrate utilization, and the thermic effect of food in moderately obese women.

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.     

Differences in resting metabolic rate between paraplegic and able-bodied subjects are explained by differences in body composition

BACKGROUND: Little is known about the relation between body composition and energy metabolism in paraplegia. OBJECTIVE: We investigated the relation between body composition and energy metabolism in healthy paraplegics as compared with able-bodied control subjects. We hypothesized that paraplegics would have lower fat-free mass (FFM), body cell mass (BCM), resting metabolic rate (RMR), and thermic effect of feeding (TEF). DESIGN: This cross-sectional study included 34 control subjects and 28 paraplegics (mean age: 29.1 +/- 7.6 and 33.9 +/- 9.2 y, respectively) with body mass indexes (in kg/m(2)) of 23.5 +/- 1.8 and 24.3 +/- 6.0, respectively. We measured RMR and TEF with indirect calorimetry, total body water with deuterium dilution, and extracellular water with corrected bromide space. We calculated FFM (total body water/0.732) and BCM [(total body water - extracellular water)/0.732)]. RESULTS: FFM was higher in control subjects than in paraplegics (77.2 +/- 7.2% and 69.2 +/- 8.7%, respectively; P = 0.0002), as were BCM (47.4 +/- 6.7% and 35.9 +/- 8.1%, respectively; P < 0.0001) and RMR (7016 +/- 935 and 6159 +/- 954 kJ/d, respectively; P = 0.0007). FFM was the single best predictor of RMR in both groups (r(2) = 0.83 for control subjects and 0.70 for paraplegics, P < 0.0001 for both). RMR adjusted for FFM did not differ significantly between control subjects and paraplegics (6670 +/- 504 and 6588 +/- 501 kJ/d, respectively). TEF also did not differ significantly between control subjects and paraplegics (6.25 +/- 2.2% and 5.53 +/- 1.8% of energy intake, respectively). CONCLUSIONS: FFM, BCM, and RMR, but not obligatory TEF, are lower in paraplegics than in control subjects. RMR does not differ between control and paraplegic subjects after adjustment for FFM, indicating similar metabolic activity in the fat-free compartment of the body.     

Leptin and body weight regulation in patients with anorexia nervosa before and during weight recovery

BACKGROUND: Leptin has been considered a starvation hormone, but its role in malnourished patients is unknown. OBJECTIVE: We aimed to characterize the role of leptin in metabolic adaptation in women with anorexia nervosa (AN). DESIGN: In a cross-sectional study, 57 women with AN [mean (+/-SD) body mass index (kg/m(2)) on admission: 15.2 +/- 1.5] were compared with 49 healthy, normal-weight women (mean body mass index: 22.3 +/- 2.3). Nineteen patients were reinvestigated during weight gain 43 and 84 d after baseline. We measured serum concentrations of leptin, soluble leptin receptor, insulin, ghrelin, and thyroid hormones [thyrotropin, triiodothyronine (T(3)), and thyroxine]; fat mass (FM) and fat-free mass (FFM); resting energy expenditure (REE); energy intake; and eating behavior. RESULTS: Compared with values in the control women, leptin, T(3), REE, FM, and FFM were lower in the women with AN, but the leptin secretion rate was not significantly different. Leptin correlated with FM (r = 0.83, P < 0.001), T(3) (r = 0.68, P < 0.001), respiratory quotient (r = -0.47, P < 0.001), and REE (r = 0.58, P < 0.001). The association with REE weakened after adjustment for FFM and disappeared after further adjustment for T(3). Hunger and appetite had positive, whereas satiety and restraint had negative, associations with leptin. During weight gain (9.0 +/- 3.3 kg in 84 d), serum leptin and the leptin secretion rate increased. Changes in leptin secretion were associated with energy intake and REE. The initial changes in the leptin secretion rate (ie, the difference between baseline and 43 d) were negatively associated with changes in body weight from 43 to 84 d. CONCLUSIONS: Leptin contributes to metabolic adaptation in women with AN. The leptin response is associated with weight gain.