Effects of exercise training on resting energy expenditure during caloric restriction

Resting energy expenditure (REE), maximum oxygen uptake (VO2max), and body composition were measured in seven moderately obese women during 9 wk of dietary restriction (800 kcal/d). During weeks 4-6, subjects underwent exercise training (30 min cycling/d, 5 d/wk, at 70% VO2max). The first 3 wk of caloric restriction decreased REE by 13% (from 1437 +/- 76 to 1254 +/- 66 kcal/24 h, means +/- SEM, p less than 0.05). Exercise training increased VO2max (from 1717 +/- 108 to 1960 +/- 120 mL/min, means +/- SEM, p less than 0.05) but did not elevate the dietary-depressed REE (from 1254 +/- 66 to 1262 +/- 62 kcal/24 h). The greatest decrease in body fat (3.7 +/- 0.4 kg) occurred during exercise training, resulting in a small apparent increase in REE when expressed per kilogram total body weight. However, expressed per unit lean body mass, REE remained suppressed throughout the period of caloric restriction. We conclude that exercise training of sufficient intensity to substantially increase VO2max does not reverse the dietary-induced depression of REE.     

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.     

The influence of nutritional intervention on resting energy expenditure in obese adolescents aged 15-18 years

The aim of this research was to assess the influence of dietary intervention on weight loss and resting energy expenditure (REE) in 20 obese and overweight adolescents (BMI = 29 +/- 3,8 kg/m2) aged 15-18 years. Nutritional habits and nutritional status were estimated before and after the introduction of low-calorie diet. Measurements of REE were carried out by indirect calorimetry in a respiratory chamber Nutritional intervention had a significant influence in decreasing body weight (from 85 +/- 14.3 kg to 82.5 +/- 12.8 kg), BMI and fat mass. Muscle mass was found to be significantly elevated (p < 0.050). REE did not decline significantly due to nutritional intervention (p > 0.05; p = 0.84).     

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 effect of a high protein-low calorie diet on the energy expenditure of obese adolescents.

Resting energy expenditure (REE), and body composition, as fat-free mass (FFM) and fat mass, were determined in seven obese adolescents before and after weight loss of a mean 13.5 kg on an approximately 800 kcal/d (3349 kJ), high protein reducing diet regimen. Ideal body weight decreased from 166% to 142% in 8 weeks. There were no significant changes in total body potassium (TBK), extracellular water (ECW), intracellular water (ICW) or total body water (TBW) with weight loss. The REE (kcal/d) fell from 2034 +/- 392 (8514 +/- 1641 kJ) to 1762 +/- 453 (7376 +/- 1896 kJ) with weight loss (P < 0.05). However, when the REE was expressed as kcal/body weight there was no difference between before and after weight loss, 21.4 +/- 2.8 (90 +/- 21 kJ) and 21.6 +/- 4.5 (90 +/- 19 kJ). Similarly, when REE was examined in relation to FFM (kcal/kg) before and after weight loss, there were also no significant differences: 34.6 +/- 5.1 (145 +/- 21 kJ) and 32.1 +/- 7.9 (134 +/- 33 kJ).     

Weight loss due to energy restriction suppresses cholesterol biosynthesis in overweight, mildly hypercholesterolemic men.

Mechanisms explaining the decrease in circulatory cholesterol levels after weight loss remain ill defined. The objective was to examine effects of weight loss as achieved through energy restriction upon human in vivo cholesterol biosynthesis. Six subjects (64-77 y, body mass index, 30.3 +/- 3.8 kg/m(2)) were recruited into a two-phase prospective clinical trial. In the first phase, subjects complied with American Heart Association (AHA) Step I diets for 3 mo with no change in their usual energy intake. After this weight-stable phase, subjects consumed an AHA Step I diet with a targeted reduction in energy intake of approximately 1000 kJ/d for 6 mo to achieve negative energy balance leading to weight loss. The incorporation rate of deuterium from body water into erythrocyte membrane free cholesterol over 24 h was utilized as an index of cholesterogenesis at the end of both phases. Subjects' mean weights decreased (P < 0.05) from 89.3 +/- 12.5 kg to 83.2 +/- 11.5 kg (6.8 +/- 2.6% of initial body weight) across phases. Circulating concentrations of total and LDL-cholesterol, and triglycerides also decreased (P < 0. 05) across phases. HDL-cholesterol concentrations were unchanged (P > 0.05). Cholesterol fractional synthetic rate (FSR) after phase 2 (3.04 +/- 1.90%/d) was lower (P < 0.05) than that after phase 1 (8. 42 +/- 3.90%/d). Absolute synthesis rate (ASR) after phase 2 [0.59 +/- 0.38 g/(kg. d)] also was lower (P < 0.05) than that after phase 1 [1.66 +/- 0.84 g/(kg. d)]. These data suggest that, in obese men, energy restriction resulting in even modest weight loss suppresses endogenous cholesterol synthesis, which contributes to a decline in circulating lipid concentrations.     

An underfeeding study in healthy men and women provides further evidence of impaired regulation of energy expenditure in old age

The effect of aging on energy regulation remains controversial. We compared the effects of underfeeding on changes in energy expenditure and respiratory quotient in young normal weight men and women [YNW, age 25.7 +/- 3.2 y(SD), body mass index (BMI) 23.1 +/- 1.6 kg/m(2)], young overweight men and women (YOW, age 26.1 +/- 3.5 y, BMI 27.7 +/- 2.1 kg/m(2)) and older (OLD) men and women (age 68.4 +/- 3.3 y, BMI 27.4 +/- 3.4 kg/m(2)). The thermic effect of feeding (TEF) during weight maintenance, and changes in resting energy expenditure (REE) and respiratory quotient were determined in response to undereating by an average 3.75 MJ/d for 6 wk. In addition, body composition was measured. No significant differences among the groups were observed in TEF, fasting and postprandial respiratory quotient, or the change in fasting respiratory quotient with underfeeding. However, REE adjusted for fat-free mass and fat mass was significantly lower in OLD subjects compared with YNW and YOW subjects (P < 0.05). In addition, the REE response to weight change was significantly attenuated in the OLD subjects (P = 0.023). These data suggest that the responsiveness of energy expenditure to negative energy balance is attenuated in old age, and provide further support for the hypothesis that mechanisms of energy regulation are broadly disregulated in old age.     

Energy expenditure is very high in extremely obese women

To test the hypothesis that total energy expenditure (TEE) and resting energy expenditure (REE) are low in extremely obese individuals, factors that could contribute to maintenance of excess weight, a cross-sectional study was conducted in 30 weight stable, extremely obese women [BMI (mean +/- SEM) 48.9 +/- 1.7 kg/m(2)]. TEE was measured over 14 d using the doubly labeled water method, REE and the thermic effect of feeding (TEF) were measured using indirect calorimetry, and activity energy expenditure (AEE) was calculated as TEE - (REE + TEF). Body composition was determined using a 3-compartment model. Subjects were divided into tertiles of BMI (37.5-45.0; 45.1-52.0; and 52.1-77.0 kg/m(2)) for data analysis. TEE and REE increased with increasing BMI tertile: TEE, 12.80 +/- 0.5, 14.67 +/- 0.5, and 16.10 +/- 0.9 MJ/d (P < 0.01); REE, 7.87 +/- 0.2, 8.78 +/- 0.3, and 9.94 +/- 0.6 MJ/d (P < 0.001), and these values were 29-38% higher than published means of measured TEE in nonobese individuals. No significant differences were observed among BMI tertiles for AEE, TEF, or physical activity level (PAL = TEE/REE, overall mean 1.64 +/- 0.16). The Harris-Benedict and WHO equations provided the closest estimates of REE (within 3%), whereas the obese-specific equations of Ireton-Jones overpredicted (40%) and Bernstein underpredicted (21%) REE. Extremely obese individuals have high absolute values for TEE and REE, indicating that excess energy intake contributes to the maintenance of excess weight. Standard equations developed for nonobese populations provided the most accurate estimates of REE for the obese individuals studied here. REE was not accurately predicted by equations developed in obese populations.     

Determinants of free-living energy expenditure in normal weight and obese women measured by doubly labeled water

Total free-living energy expenditure (TEE) was measured in 9 normal weight controls and 5 obese women using the doubly labeled water (DLW) method. Resting energy expenditure (REE) and the thermic effect of food (TEF) were measured by indirect calorimetry and the energy cost of physical activity (PA) calculated by deduction, in order to quantify the components and identify determinants of free-living TEE. Although REE was quantitatively the major component of TEE in both groups, PA best explained the variability, contributing 76% to the variance in free-living TEE. The obese women had elevated values for TEE (12397 +/- 2565 vs. 8339 +/- 1787 kJ/d, mean +/- SD; p < 0.005), compared with the control women. PA (5071 +/- 2385 vs. 2552 +/- 1452; p < 0.05) and REE (6393 +/- 678 vs. 5084 +/- 259; p < 0.0005) were also raised in the obese, whereas TEF was not significantly different between the groups, accounting for 7.6% of energy expenditure for the obese and 8% for the control subjects. Body weight was the single best determinant of mean daily free-living TEE across both groups. We conclude that PA and body weight are the main determinants of free-living TEE.     

An evaluation of resting energy expenditure in hospitalized, severely underweight patients.

A prospective trial was conducted with 14 hospitalized patients who were severely underweight with a mean weight of 40.9+/-5.1 kg and 70.7+/-7.8% of ideal body weight, to compare estimates of resting energy expenditure (REE) with measured values. The 9 women and 3 men, whose mean age was 66.5+/-13.9 y, underwent nutritional assessment and measurement of their REE by indirect calorimetry using the Sensormedics Deltatrac MBM100 indirect calorimeter. Their REE was also estimated by the Harris-Benedict formula (mean 1032+/-66 kcal/d) as well as a previously established empirical formula where REE = 25 x body weight in kg (mean 1023+/-129 kcal/d). Results by both estimates were significantly lower than the measured resting energy expenditure (MREE) in this group of patients (P<0.0001). The percentage difference between MREE and estimated REE by the Harris-Benedict formula was 18.4+/-9.4% and 20.9+/-7.5% by the empirical formula. The MREE exceeded the estimated REE in each individual. The correlation between MREE and body weight (r2 = 0.558, r = 0.005) was better than that between MREE and estimated REE by Harris-Benedict formula (r2 = 0.275, P = 0.08) suggesting that weight was the principal determinant rather than the other components (height, age, sex) of the Harris-Benedict formula. Our data shows that commonly employed formulae routinely underestimate the energy needs of severely underweight patients below 50 kg in body weight. The Harris-Benedict equation had limited predictive value for the individual, explaining approximately 25% of the variance in energy expenditure. Given the particular importance of matching energy intake to needs in this group of patients with limited reserves, many of whom are critically ill, we suggest an empirical equation using 30-32 kcal/kg be used to estimate the energy requirements of severely underweight patients when direct measurements are unavailable or clinically less imperative.     

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.     

Use of [14C]-sodium bicarbonate/urea to measure total energy expenditure in overweight men and women before and after low calorie diet induced weight loss

The aim of this study was to evaluate the use of the [14C]-sodium bicarbonate/urea technique to measure the change in total energy expenditure after weight loss and a period of weight maintenance. Eleven healthy subjects (6 men and 5 women aged 50 +/- 3 yrs, BMI 34.1 +/-2.1 kg/ m2, body fat 38.7 +/-3%) underwent 8 weeks of energy restriction using a combination of "Modifast" formula and one small meal per day (approximately 3.3 MJ/day). For an additional 2 weeks, subjects resumed a solid food diet that contained enough energy to stabilize body weight at the newly reduced level. Body composition, total energy expenditure (TEE), resting energy expenditure (REE) and the thermic effect of a 2.7 MJ test meal (TEF) were measured at both weeks 0 and 10. At week 10 as compared to week 0, body weight decreased by 12.2+/-1.6 kg (12.5%)(P<0.001). Total fat and lean mass decreased by 8.4+/-1.0 kg (20.4%) and 3.8+/-0.7 kg (6.7%), respectively (P< 0.001). REE decreased by 500+/-128 kJ/day (5.6+/-1.3%)(P<0.002). Decreases in the TEE (0.18 +/-;3.7%)and TEF(1.4+/-0.9%) were not significant. In conclusion, although [14C]-sodium bicarbonate/urea was well tolerated and did not interfere with normal daily activities, it did not have sufficient sensitivity to accurately measure weight loss induced changes in TEE in the range of 0.1-10%.     

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.     

Effect of insulin and energy restriction on the thermic effect of protein in type 2 diabetes mellitus

OBJECTIVE: The objective of this study was to test whether the thermic effect of oral protein is blunted in poorly controlled type 2 diabetes and is corrected by normalization of glycemia with insulin and 28 days of a very-low-energy diet. RESEARCH METHODS AND PROCEDURES: Resting energy expenditure (REE) and the thermic effect of 90 g of oral protein were measured, using indirect calorimetry, in nine (five women and four men) obese diabetic people [weight, 108 +/- 10 kg; waist circumference, 123 +/- 8 cm; body mass index, 40 +/- 3 kg/m(2)] who were hyperglycemic on day 8 or euglycemic with insulin on day 16 of a weight-maintaining diet and euglycemic on day 28 of a very low energy diet (VLED). Results were compared with those of seven (six women and one man) weight- and body mass index-matched obese nondiabetic subjects with a waist circumference of 111 +/- 6 cm. Substrates and hormonal responses were determined concurrently. RESULTS: Fasting glucose was normalized in the diabetic subjects with insulin from day 9 of VLED onward. Weight decreased in both groups by 9.9 +/- 0.9 kg with VLED. REE was 8 +/- 2% lower with insulin treatment and decreased by another 14 +/- 3% with VLED in the diabetic and by 15 +/- 1% in the nondiabetic subjects by week 4. After the protein meal, the thermic response was significantly (p < 0.05) less with hyperglycemia than with insulin-induced euglycemia, as percentage above REE (15.3 +/- 1.4 compared with 21.2 +/- 1.5%), as percentage of the energy content of the meal (19.5 +/- 1.5 compared with 25.2 +/- 1.7%), as kilocalories per 405 minutes (86 +/- 5 compared with 110 +/- 7), and less than in nondiabetic obese controls (21.0 +/- 2.2% above REE, 24.4 +/- 1.7% of energy of meal). After the VLED, the thermic effect of protein was significantly higher in both groups only as percentage above REE. The initial glucagon response was greater with hyperglycemia compared with euglycemia and post-VLED but not compared with the nondiabetic subjects. Hyperglycemia was associated with 21 +/- 4% greater urinary urea nitrogen excretion and urinary glucose losses of 134 +/- 50 mmol/d. DISCUSSION: This study shows a blunted thermic effect of protein in obese hyperglycemic type 2 diabetic subjects compared with matched nondiabetic subjects that can be corrected with insulin- or energy restriction-induced euglycemia.     

Predicting energy expenditure in extremely obese women

BACKGROUND: The most common clinical method for resting energy expenditure (REE) assessment is prediction equations. The purpose of this study was to elucidate which prediction equation is most accurate for REE assessment in extremely obese women. METHODS: Fourteen extremely obese women (mean +/- SD body mass index: 49.8 +/- 6.2 kg/m(2); age: 49 +/- 10 years) were measured for height and weight and REE via indirect calorimetry (IC) by a metabolic cart system. Predicted REE was evaluated by several equations, including Harris-Benedict with actual body weight, Harris-Benedict with several adjustments to body weight, Cunningham, Mifflin-St Jeor, Owen, World Health Organization (WHO), and Bernstein equations. Accuracy was determined by mean difference data (IC REE - equation REE; Student's paired t-test), correlation coefficients, and agreement between methods by Bland-Altman plots. Accuracy was also evaluated on an individual basis, defined by the percentage of individuals within +/-10% of IC REE. RESULTS: The Mifflin-St Jeor, Harris-Benedict with actual body weight, and the WHO equations were the most accurate in terms of mean predicted REE. The mean predicted REE values by all other equations were different from the IC REE values (p < .1). According to the individual data, the Mifflin-St Jeor was most accurate (14% outside +/-10% IC REE). The Harris-Benedict with actual body weight and WHO equations were less accurate on individual terms, with 29% and 42% of the predicted REE values, respectively, falling outside +/-10% of IC REE. CONCLUSIONS: The Mifflin-St Jeor equation was most accurate method for REE assessment in extremely obese women.     

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.     

Aging and energy expenditure

Whether sedentary energy expenditure is normal or lower in elderly people has not yet been clearly established. Twenty-four-hour energy expenditure (24EE) and its different components were measured by use of a respiratory chamber in elderly (17 male, 21 female; 71 +/- 6 y, mean +/- SD; 71.2 +/- 13.5 kg; 32 +/- 8% fat) and young (33 male, 31 female; 24 +/- 4 y; 84.5 +/- 23.1 kg; 25 +/- 13% fat) subjects. The elderly subjects had lower mean height (P less than 0.001), weight (P less than 0.01), and fat-free mass (P less than 0.001) but higher percent body fat (P less than 0.01) than did the young adults. Absolute 24EE, basal metabolic rate (BMR), and sleeping metabolic rate were significantly lower (P less than 0.01) in the elderly subjects than in the young subjects. However, after differences in fat-free mass, fat mass, and sex were adjusted for, only BMR was found to be lower in the elderly subjects (P less than 0.01). Despite a reduced adjusted BMR in older subjects, sedentary 24EE was decreased only in proportion to their reduced body size, suggesting that the lower energy intake reported in elderly people might be mainly related to lower physical activity in free-living conditions.     

Research on energy expenditure in individuals with eating disorders: a review

OBJECTIVE: This study reviews the published research on energy expenditure in individuals with anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). METHOD: Individual studies are reviewed and their results summarized. RESULTS: The most consistent finding is evidence of reduction in resting energy expenditure (REE) in patients with AN, which increases with increased energy intake and body weight. Data regarding BN are inconsistent. Three available studies in subjects with BED have not found evidence of changes in energy expenditure corrected for lean body mass compared with obese non-binge eaters. DISCUSSION: The ability to reliably and cost-effectively measure REE may aid in the refeeding of patients with AN where REE is reduced. Changes in BN and BED subjects have yet to be identified consistently.     

Dietary energy requirements of young adult men, determined by using the doubly labeled water method

We examined the hypothesis that current recommendations on dietary energy requirements may underestimate the total energy needs of young adult men, by measuring total energy expenditure (TEE) and resting energy expenditure (REE) in 14 weight-maintaining healthy subjects leading unrestricted lives. TEE and body composition were measured by using 2H(2)18O, and REE was measured by using indirect calorimetry. All subjects had sedentary full-time occupations and participated in strenuous leisure activities for 34 +/- 6 (SE) min/d. TEE and REE were 14.61 +/- 0.76 and 7.39 +/- 0.26 MJ/d, respectively, and 202 +/- 2 and 122 +/- 2 kJ.kg-1.d-1. There were significant relationships between TEE and both body fat-free mass (r = 0.732, P less than 0.005) and measured REE (r = 0.568, P less than 0.05). Measured TEE:REE values were significantly higher than the recommended energy requirement (1.98 +/- 0.09, compared with 1.55 or 1.67, P less than 0.005). These results are consistent with the suggestion that the current recommended energy intake for young adult men may underestimate total energy needs.     

Reduction in energy expenditure after liver transplantation.

After successful liver transplantation (LTx), excessive weight gain is common among recipients. This rapid change in body morphology has been attributed to immunosuppressive regimens. The liver's role as a metabolic sensor and its autonomic innervation are pivotal in relaying humoral and neural information to the hypothalamus, where ingestive behavior is determined and has largely been ignored. We examined and assessed the contribution of drugs, energy intake, and energy expenditure on weight gain after LTx. Twenty-three patients were followed up at 3-mo intervals after LTx. Energy expenditure was measured by indirect calorimetry and dietary intake by diet diaries, and body composition was assessed with anthropometry and multifrequency bioelectrical impedance analysis. Cumulative drug doses were calculated, and associations between body composition and immunosuppressive regimens and energy expenditure were examined. Nine months after LTx, 20 of 23 (87%) recipients were overweight or obese, despite three-fourths of this cohort being on weight-reduction regimens. After LTx, a decrease in measured energy expenditure was observed (60.3 +/- 1.6 kJ/kg of body cell mass pre-LTx versus 53.7 +/- 2.2 kJ/kg of body cell mass after 9 mo; P < 0.05). Multiple stepwise regression analysis showed that, when adjusted for body weight, the strongest predictor of fat mass at 9 mo after LTx was resting energy expenditure. Weight gain after LTx is not predicted by immunosuppressive drug dosage. The strong association between weight gain and energy economy might be a consequence of the loss of hepatic metabolic integration and accelerated further by increased energy intake. Effective management of weight gain will not be achieved until the mechanisms involved in altered energy homeostasis are elucidated.