Whole-body protein anabolic response is resistant to the action of insulin in obese women

BACKGROUND: Obesity is associated with insulin resistance of glucose and lipid metabolism. OBJECTIVE: We sought to determine the effects of obesity on the insulin sensitivity of protein metabolism. DESIGN: Whole-body [(13)C]leucine and [(3)H]glucose kinetics were measured in 9 lean and 10 obese women in the postabsorptive state and during a hyperinsulinemic, euglycemic, isoaminoacidemic clamp. RESULTS: In the postabsorptive state, the leucine endogenous rate of appearance (catabolism), normalized for fat-free mass, was 11% greater and the nonoxidative rate of disappearance (synthesis) was 8% greater in the obese than in the lean women, but net balance was 29% more negative (P < 0.05). Clamp amino acid and glucose infusion rates were significantly lower in the obese women than in the lean women (0.65 +/- 0.02 compared with 0.85 +/- 0.04 and 5.7 +/- 0.3 compared with 9.1 +/- 0.5 mg x kg fat-free mass(-1) x min(-1), respectively; P < 0.0001 for both), and their rates correlated positively (r = 0.635, P = 0.005). During hyperinsulinemia, synthesis was stimulated less and net leucine balance was much lower in the obese women than in the lean women (-0.08 +/- 0.06 and 0.30 +/- 0.03 mumol x kg fat-free mass(-1) x min(-1), respectively; P < 0.0001). The percentage change in net leucine balance correlated negatively with all adiposity indexes. Plasma free fatty acids were less suppressed and the respiratory quotient was lower in the obese women than in the lean women. CONCLUSION: Obese women show a blunted protein anabolic response to hyperinsulinemia that is consistent with resistance to the action of insulin on protein concurrent with that on glucose and lipid metabolism.     

Resting energy expenditure is not increased in mildly hyperglycaemic obese diabetic patients

Resting energy expenditure (REE) is believed to be increased in type 2 diabetes, an increase that is associated with deteriorating glucose tolerance during its development. Meanwhile, insulin resistance, a state linked to obesity and observed in all type 2 diabetic patients, is associated with reduced REE. Our aim was to compare REE in obese patients with and without diabetes. REE, body composition (total body water, density, percentage fat and fat-free mass: 3-compartment model) and metabolic control were assessed in fifty obese Caucasian patients with diabetes (glycated haemoglobin level 7.6 (SD 1.5) %) and fifty obese patients who were non-diabetic. Despite being more overweight and younger, obese non-diabetic patients had an absolute REE (7.73 (SD 1.44) v. 8.12 (SD 1.37) MJ; P=0.17) and percentage fat-free mass similar to those of obese diabetic patients. Even when adjusted for differences in body composition, REE remained similar in both groups. Furthermore, REE (absolute and adjusted) was unaffected by both glucose level and control (glycated haemoglobin), with fat-free mass being the only determinant of REE. We conclude that REE is not necessarily increased by the presence of diabetes in obese people.     

Body Composition, Dietary Intake, and Energy Expenditure in Nonobese, Prepubertal Children of Obese and Nonobese Biological Mothers

Objective To determine differences in dietary intake, resting energy expenditure, activity level, fat-free mass, and percentage body and abdominal fat in nonobese children of obese mothers compared with nonobese children of nonobese mothers.Design Cross-sectional comparison study. Children's food diaries were analyzed to determine average energy and nutrient content. Resting energy expenditure of children was measured by means of indirect calorimetry. Children's activity levels were estimated through questionnaires administered during interviews. Dual-energy x-ray absorptiometry was used to estimate body composition of children.Subjects Mothers of subjects responded to advertisements and were recruited as nonobese (body mass INDEX=20 to 25) or obese (body mass index ≥30). Offspring included in the study were prepubertal and nonobese (10th to 90th percentile of weight for height by gender). Twelve pairs of children could be matched for weight, gender, and age.Statistical analysis performed Wilcoxon signed rank tests were used to determine differences between the 2 groups of children.Results Percentage abdominal fat was greater (median DIFFERENCE=3.15, P=.001) and fat-free mass was lower (median DIFFERENCE=1.19, P=.04) in children of obese mothers compared with children of nonobese mothers. No statistically significant differences between the 2 groups of children were found for dietary intake, resting energy expenditure, activity level, or percentage body fat.Applications/conclusions The significantly higher percentage of abdominal fat and lower fat-free mass in children of obese mothers may contribute to obesity onset. Use of dual-energy x-ray absorptiometry as a screening tool for nonobese, prepubertal children with an obese parent will help to identify those at risk. Education and lifestyle changes can then be implemented to help prevent the onset of obesity. J Am Diet Assoc. 1999;99:58-65.     

Familial resemblance of body composition in prepubertal girls and their biological parents

BACKGROUND: Heritability estimates for body mass index (BMI; in kg/m(2)) in children generally have been derived from twin and adoption studies. However, BMI does not reflect total or regional body composition. OBJECTIVE: We evaluated the familial resemblance of body composition between prepubertal girls of normal weight and body fatness and their parents by using state-of-the-art technology. DESIGN: The subjects were 101 girls [mean age: 8.5 +/- 0.4 y; percentage body fat (%BF): 12-30%] and their biological parents. Weight, height, and body composition [fat mass (FM), fat-free mass (FFM), and %BF] were measured with dual-energy X-ray absorptiometry (DXA) and total body potassium (TBK). RESULTS: Weight, height, and BMI showed low-to-moderate similarity between the girls and both their parents (r = 0.29-0.44, P < 0.01). The girls' FM, FFM, and %BF were significantly related to both parents' body composition. Cross-generational equations were developed for DXA, eg, child's %BF = 12.4 + (0.158 paternal %BF) + (0.145 maternal %BF) (adjusted r(2) = 0.16, P < 0.001). Regional analysis with DXA showed that the adjusted r(2) values for the arm, trunk, and leg regions, respectively, were 0.17, 0.33, and 0.31 for lean tissue mass and 0.11, 0.14, and 0.09 for FM. TBK showed a similar relation between parents and girls (r = 0.28-0.47, P < 0.01). Significant heritability (h(2) +/- SE) was detected for BMI (0.35 +/- 0.17, P = 0.03) and %BF measured with DXA (0.50 +/- 0.12, P = 0.0001). CONCLUSION: The body composition of prepubertal girls of normal weight and body fatness is significantly related to the body composition of both biological parents.     

Use of the leg-to-leg bioelectrical impedance method in assessing body-composition change in obese women

BACKGROUND: There is little information on whether bioelectrical impedance analysis (BIA) accurately predicts changes in body composition associated with energy restriction, exercise, or both. OBJECTIVE: We had 2 objectives: to determine the validity of the leg-to-leg BIA system in 1) estimating body composition in obese and nonobese women, with a cross-sectional design, and 2) assessing changes in body composition in obese women in response to 12 wk of energy restriction, exercise training, or both. DESIGN: Subjects were 98 moderately obese women (43.2 +/- 0.6% body fat, 45.0 +/- 1.1 y of age) and 27 nonobese control subjects (24.0 +/- 1.5% body fat, 43.5 +/- 2.5 y of age). Obese subjects were randomly divided into 1 of 4 groups, with fat-free mass, fat mass, and percentage body fat estimated with BIA and underwater weighing before and after 12 wk of intervention. The 4 groups were diet only (4.19-5.44 MJ/d), exercise only (five, 45-min sessions/wk at 78.5 +/- 0.5% of maximum heart rate), both exercise and diet, and control (no diet or exercise). RESULTS: No significant difference was found between underwater weighing and BIA in estimating the fat-free mass of the obese and nonobese women (all subjects combined, r = 0.78, P < 0.001, SEE = 3.7 kg) or in estimating decreases in fat mass during 12 wk of energy restriction, exercise, or both in obese subjects (F[3.85] = 1.45, P = 0.233). CONCLUSIONS: The leg-to-leg BIA system accurately assessed fat-free mass in obese and nonobese women, and changes in fat mass with diet alone or when combined with exercise.     

Age, sex, ethnicity, body composition, and resting energy expenditure of obese African American and white children and adolescents

BACKGROUND: African Americans may have a lower resting energy expenditure (REE) than do whites, although the data are limited for obese children and adolescents and for boys. Differences in bone density and trunk lean body mass may account for some of these measured differences in REE. OBJECTIVE: We assessed the REE and body composition of obese African American and white children and adolescents. DESIGN: Obese, 5-17-y-old children and adolescents were evaluated (n = 203). Body composition was assessed by dual-energy X-ray absorptiometry. REE was measured by open-circuit calorimetry. African American and white children were compared. The relation between REE and the independent variables (age, sex, ethnic group, fat mass, and fat-free mass or lean tissue mass) was assessed. RESULTS: Of those evaluated, 66% were girls and 34% were African American. Age, sex, pubertal status, and body composition did not differ significantly by ethnic group. All the independent variables were significantly associated with REE. Using lean tissue mass to account for differences in bone density did not significantly alter the results. REE decreased with age and was lower in the girls than in the boys and in the African Americans than in the whites. When trunk fat-free mass was included in the model in place of whole-body fat-free mass, the ethnic difference in REE decreased. CONCLUSIONS: Adjustment for trunk lean tissue mass partially explains the lower REE of obese African American children and adolescents. The lower relative REE of older obese children suggests the importance of early intervention in the prevention of childhood obesity. The lower REE of girls and of African Americans may contribute to the difficulty in weight management in these groups.     

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).     

Exercise affects protein utilization in healthy children

Although health initiatives promote increased physical activity in children, the physiologic outcomes have not been well characterized. This investigation examined the effects of programmed aerobic exercise on protein metabolism in children (n = 7; mean +/- SEM: 9.14 +/- 0.46 y old; weight, 32.1 +/- 1.6 kg; height, 138 +/- 2.5 cm; and body mass index, 16.21 +/- 0.36 kg/m(2) ) using (15)N-glycine methodology. Boys (n = 5) and girls (n = 2) walked (5 d/wk, 3.2-6.4 km/d) for 6 wk. Criterion measures taken at baseline (Pre) and after the exercise program (Post) included anthropometric data, dietary assessment, nitrogen balance, nitrogen flux (Q), protein synthesis (PS), protein breakdown (PB) and net protein balance [(Net) = PS - PB]. After the walking program, there were no significant changes in body weight, fat-free mass or percentage of body fat, whereas height increased (P < 0.01). Energy and protein intakes were constant throughout the study. Nitrogen balance was significantly more positive Post than Pre (P < 0.05). There was a significant decrease in Q (P < 0.0001) with corresponding decreases in PS (P < 0.001) and PB (P < 0.01). These data provide the first evidence that programmed aerobic exercise alters whole-body protein utilization in healthy, nonobese children. Longitudinal studies are required to further examine changes in protein metabolism associated with increased physical activity in this population. In addition, findings suggest a need to evaluate nutrient requirements for healthy, physically active boys and girls.     

Assessment of whole body protein metabolism in critically ill children: can we use the [15N]glycine single oral dose method?

BACKGROUND & AIMS: Most stable-isotope methods to evaluate whole body protein metabolism in patients are invasive and difficult to use in children. In this study protein metabolism was evaluated with the non-invasive [15N]glycine single oral dose method in critically ill children and the value of the method is discussed. METHODS: [15N]glycine (100mg) was given orally to children (mean age 5.5 years; range 0.6-15.5 years) with meningococcal septic shock (MSS, n = 8), pneumonia (n = 5), and to healthy, fed and post-absorptive children (n = 10). Urine was collected during 9h, total amount of NH(3), labelled NH(3) and nitrogen were measured, and protein turnover, synthesis and breakdown were calculated using urinary NH(3) as end-product. RESULTS: Mean protein turnover in children with MSS, pneumonia and fed and post-absorptive healthy children was 0.63+/-0.13, 0.38+/-0.10, 0.28+/-0.03 and 0.28+/-0.02g N/kg/9h, respectively. Mean protein synthesis was 0.55+/-0.12, 0.29+/-0.09, 0.18+/-0.02, 0.20+/-0.02g N/kg/9h, respectively. Mean protein breakdown was 0.56+/-0.14, 0.28+/-0.12, 0.08+/-0.03, 0.28+/-0.02g N/kg/9h, respectively. Protein turnover, synthesis and breakdown were significantly increased in MSS patients compared to fed healthy children (P <0.01) and post-absorptive children (P <0.05). Protein turnover, protein synthesis, protein breakdown were significantly correlated with disease severity and body temperature (P <0.05). CONCLUSION: Results of whole body protein metabolism measured with the [15N]glycine single oral dose method in children with MSS and in healthy children were in line with expectations based on results obtained in earlier reports and with different methods.     

Energy expenditure at rest and during sleep in children with Prader-Willi syndrome is explained by body composition

BACKGROUND: Obesity in Prader-Willi syndrome (PWS) seems to be related to a low basal metabolic rate (BMR). In addition, abnormal sleep patterns reported in PWS might affect sleeping metabolic rate (SMR). OBJECTIVE: Our objective was to assess BMR and SMR adjusted for fat-free mass in young PWS patients. DESIGN: Subjects were 17 PWS patients (10 females and 7 males aged 7.5-19.8 y) and 17 obese control subjects matched for sex and bone age. SMR was measured in a respiratory chamber, BMR with a ventilated-hood system, and body composition by deuterium dilution. RESULTS: BMR and SMR were significantly lower in the PWS group than in the control group (5.36 +/- 1.18 and 4.62 +/- 1.08 MJ/d compared with 6.38 +/- 1.55 and 5.60 +/- 1.52 MJ/d, respectively; P < 0.05). When fat-free mass was included in the analysis, multiple regression showed no differences in BMR and SMR between groups. When weight was included in the analysis instead of fat-free mass, SMR was lower in the PWS group. Fat-free mass was lower in the PWS group both as an absolute value and when adjusted for height. CONCLUSION: BMR and SMR are low in young patients with PWS because of a low fat-free mass.     

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

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

Familial influences and obesity-associated metabolic risk factors contribute to the variation in resting energy expenditure: the Kiel Obesity Prevention Study

BACKGROUND: A low metabolic rate may be inherited and predispose to obesity, whereas a higher metabolic rate in obesity may be acquired by obesity-associated cardiometabolic risk. OBJECTIVE: We aimed to explain the interindividual variation in resting energy expenditure (REE) by assessing 1) the association between REE and body composition, thyroid hormones, and obesity-related cardiometabolic risk factors, and 2) the familial (genetic and environmental) contribution to REE. DESIGN: REE and metabolic risk factors (ie, blood pressure and plasma insulin, glucose, and C-reactive protein concentrations) were assessed in 149 two- or three-generation families, including at least one overweight or obese member. Heritability of REE, respiratory quotient (RQ), thyroid hormones [thyrotropin (TSH), free triiodothyronine (FT3) and free thyroxine (FT4)], and body composition (fat-free mass and fat mass) were estimated by using variance components-based quantitative genetic models. RESULTS: REE adjusted for body composition, sex, and age (REEadj) significantly correlated with systolic and diastolic blood pressure, plasma insulin and glucose concentrations, and the homeostasis model assessment (HOMA) (r = 0.14-0.31, P < 0.05). Thyroid hormones had a modest influence on REE variance only. Heritability was 0.30 +/- 0.07 for REEadj and 0.29 +/- 0.08 for REE after additional adjustment for thyroid hormones and metabolic risk. Furthermore, heritability was estimated to be 0.22 +/- 0.08 for RQ, 0.37 +/- 0.08 for TSH, 0.68 +/- 0.06 for FT4, and 0.69 +/- 0.05 for FT3 (all significantly larger than zero). CONCLUSIONS: Obesity-related cardiometabolic risk factors contribute to interindividual variation in REE, with hypertension and insulin resistance being associated with a higher REE. REE was moderately heritable, independent of body composition, sex, age, thyroid function, and cardiometabolic risk.     

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.     

Body composition as a determinant of energy expenditure: a synthetic review and a proposed general prediction equation

Differences in body composition have often been examined in conjunction with measurements of energy expenditure in men and women. Numerous studies during the past decade examined the relationship between resting energy expenditure (REE) and the components of a two-compartment model of composition, namely the fat-free mass (FFM) and the fat mass (FM). A synthetic review of these studies confirms a primary correlation between REE and FFM in adults over a broad range of body weights. A generalized prediction equation is proposed as REE = 370 +/- 21.6 x FFM. This equation explains 65-90% of the variation in REE. Several studies suggest, further, that FFM predicts total daily energy expenditure (TDEE) equally well. An independent contribution by FM to the prediction of either REE or TDEE is not supported for the general population, perhaps reflecting the relative constancy of the absolute FM in nonobese individuals. In the subset of obese women, FM may be a significant predictor.     

Sex differences in resting energy expenditure and their relation to insulin resistance in children (EarlyBird 13)

BACKGROUND: Insulin resistance is believed to be the process underlying type 2 diabetes and premature cardiovascular disease. We have established that a relation between body mass and insulin resistance calculated by homeostasis model assessment (HOMA-IR) exists by 5 y of age in contemporary UK children. Resting energy expenditure (REE) is variable among individuals and is one of many factors controlling body mass. OBJECTIVE: The objective was to investigate the relations between REE, body mass, and HOMA-IR in young children. DESIGN: EarlyBird is a nonintervention prospective cohort study of 307 healthy 5-y-olds that asks the question: Which children develop insulin resistance and why? REE by indirect calorimetry and HOMA-IR were measured in addition to total body mass, fat-free mass (FFM) by bioimpedance, body mass index (BMI; in kg/m(2)), and skinfold thickness when the mean age of the cohort was 5.9 +/- 0.2 y. RESULTS: Whereas the BMI of the boys was lower than that of the girls (x +/- SD: boys, 15.9 +/- 1.9; girls, 16.5 +/- 1.9; P = 0.03), their REE was higher by 6% (x +/- SD: 4724 +/- 615 compared with 4469 +/- 531 kJ/d; P = 0.002). This difference persisted after adjustment for FFM and other anthropometric variables (P = 0.04). In boys, there was a weak, although significant, inverse correlation between REE and HOMA-IR, independent of fat mass and FFM (boys: r = -0.21, P = 0.03; girls: r = 0.12, P = 0.34). CONCLUSION: There is a sex difference in REE at 6 y of age that cannot be explained by body composition. The difference appears to be intrinsic, and its contribution to sex differences in adiposity and HOMA-IR in children merits further exploration.     

Effects of weekly administration of pegylated recombinant human OB protein on appetite profile and energy metabolism in obese men

BACKGROUND: Results of leptin administration in mice, rats, and humans provide a rationale for therapeutic augmentation of circulating leptin (OB protein) concentrations in obese humans; this may reduce food intake, increase metabolic rate, and lower body mass. OBJECTIVE: We assessed the effects of weekly subcutaneous pegylated polyethylene glycol (PEG)-OB protein administration on appetite and energy metabolism in obese men. DESIGN: We performed a randomized, double-blind, placebo-controlled trial in 30 obese men [body mass index (in kg/m(2)): 34.2 +/- 3.6; age: 44.7 +/- 7 y]. Subjects received 20 mg PEG-OB protein/wk for 12 wk while limiting their energy intake to 2.1 MJ/d. RESULTS: During treatment, appetite and hunger before breakfast decreased and remained lower in the PEG-OB-protein group, whereas they increased and remained higher in the placebo group (P < 0.0001). During treatment, hunger decreased in the PEG-OB-protein group (P < 0.05) and cognitive restraint increased in the placebo group (P < 0.0001). Neither appetite nor food intake changed significantly during the ad libitum evening meal. Under energy balance conditions in the respiration chamber, appetite at the end of treatment was not significantly different from baseline despite similar, significant reductions in 24-h energy intake, energy expenditure, sleeping metabolic rate, body mass, fat mass, and fat-free mass (P < 0.01 for all) in both groups. CONCLUSION: Treatment with PEG-OB protein modified subjective appetite at a dosage that produced no changes in body composition, energy expenditure, or body mass loss relative to placebo treatment, suggesting that PEG-OB protein has central rather than peripheral biological activity in obese men.     

Development and cross-validation of prediction equations for estimating resting energy expenditure in severely obese Caucasian children and adolescents

The objectives of the present study were to develop and cross-validate new equations for predicting resting energy expenditure (REE) in severely obese children and adolescents, and to determine the accuracy of new equations using the Bland-Altman method. The subjects of the study were 574 obese Caucasian children and adolescents (mean BMI z-score 3.3). REE was determined by indirect calorimetry and body composition by bioelectrical impedance analysis. Equations were derived by stepwise multiple regression analysis using a calibration cohort of 287 subjects and the equations were cross-validated in the remaining 287 subjects. Two new specific equations based on anthropometric parameters were generated as follows: (1) REE=(Sex x 892.68)-(Age x 115.93)+(Weight x 54.96)+(Stature x 1816.23)+1484.50 (R(2) 0.66; se 1028.97 kJ); (2) REE=(Sex x 909.12)-(Age x 107.48)+(fat-free mass x 68.39)+(fat mass x 55.19)+3631.23 (R(2) 0.66; se 1034.28 kJ). In the cross-validation group, mean predicted REE values were not significantly different from the mean measured REE for all children and adolescents, as well as for boys and for girls (difference <2 %) and the limits of agreement (+/-2 sd) were +2.06 and -1.77 MJ/d (NS). The new prediction equations allow an accurate estimation of REE in groups of severely obese children and adolescents. These equations might be useful for health care professionals and researchers when estimating REE in severely obese children and adolescents.     

Resting energy expenditure and its determinants in hemodialysis patients

OBJECTIVE: Chronic kidney disease is associated with several metabolic disturbances that can affect energy metabolism. As resting energy expenditure (REE) is scarcely investigated in patients on hemodialysis (HD) therapy, we aimed to evaluate the REE and its determinants in HD patients. DESIGN: Cross-sectional study. SETTING: Dialysis Unit of the Nephrology Division, Federal University of S?o Paulo, Brazil. SUBJECTS: The study included 55 patients (28 male, 41.4+/-12.6 years old) undergoing HD therapy thrice weekly for at least 2 months, and 55 healthy individuals pair matched for age and gender. Subjects underwent fasting blood tests, as well as nutritional assessment, and the REE was assessed by indirect calorimetry. RESULTS: REE of HD patients was similar to that of pair-matched controls (1379+/-272 and 1440+/-259 kcal/day, respectively), even when adjusted for fat-free mass (P=0.24). REE of HD patients correlated positively with fat-free mass (r=0.74; P<0.001) and body mass index (r=0.37; P<0.01), and negatively with dialysis adequacy (r=-0.46; P<0.001). No significant univariate correlation was found between REE and age, dialysis vintage, serum creatinine, urea, albumin, bicarbonate, parathyroid hormone (PTH) or high-sensitivity C-reactive protein (CRP). In the multiple linear regression analysis, using REE as dependent variable, the final model showed that besides the well-recognized determinants of REE such as fat-free mass and age, PTH and CRP were the independent determinants of REE in HD patients (R (2)=0.64). CONCLUSIONS: In this study, the REE of HD patients was similar to that of healthy individuals, even with the positive effect of secondary hyperparathyroidism and inflammation on REE of these patients.     

Energy expenditure of stunted and nonstunted boys and girls living in the shantytowns of São Paulo, Brazil

BACKGROUND: Stunting increases the risk of obesity in developing countries, particularly in girls and women, but the underlying reason is not known. OBJECTIVE: Our objective was to test the hypothesis that stunted children have lower energy expenditure than do nonstunted children, a factor that has predicted an increased risk of obesity in other high-risk populations. DESIGN: A cross-sectional study was conducted in shantytown children from S?o Paulo, Brazil. Twenty-eight stunted children aged 8-11 y were compared with 30 nonstunted children with similar weight-for-height. Free-living total energy expenditure (TEE) was measured over 7 d by using the doubly labeled water method. In addition, resting energy expenditure (REE) was measured by indirect calorimetry and body composition was measured by dual-energy X-ray absorptiometry. RESULTS: There were no significant associations between stunting and any measured energy expenditure parameter, including REE adjusted for weight (f1.gif" BORDER="0"> +/- SEM: 4575 +/- 95 compared with 4742 +/- 91 kJ/d, in stunted and nonstunted children, respectively) and TEE adjusted for weight (8424 +/- 239 compared with 8009 +/- 221 kJ/d, in stunted and nonstunted children, respectively). In multiple regression models that included fat-free mass and fat mass, girls had significantly lower TEE than did boys (P: < 0.05) but not significantly lower REE (P: = 0.17). CONCLUSIONS: There was no association between stunting and energy expenditure after differences between groups in body size and composition were accounted for. However, the girls had lower TEE than did boys, which may help to explain the particularly high risk of obesity in stunted adolescent girls and women in urban areas of developing countries.     

Hyperphagia contributes to the normal body composition and protein-energy balance in HIV-infected asymptomatic men

Wasting can occur at an early stage of HIV infection. Both reduced energy intake and increased resting energy expenditure (REE) have been considered as factors in wasting with predominant lean body mass loss, suggesting disturbances of protein metabolism. Our aim was to study protein-energy metabolism in relation to body composition and oral energy intake in asymptomatic patients with HIV infection but receiving no active antiretroviral therapy. Stable-weight asymptomatic male patients (n = 8) at stage A of HIV infection with a detectable viral load were compared with 9 healthy control men. Protein metabolism was studied in the postabsorptive state using a primed constant infusion of l-[1-(13)C]leucine and l-[2-(15)N]glutamine. REE was studied by indirect calorimetry, body composition by bioelectrical impedance, and energy intake by dietary records. BMI and lean body mass did not differ between patients and controls. In HIV-infected subjects, energy intake, protein breakdown, protein synthesis, and REE were 57% (P < 0.05), 18% (P < 0.05), 22% (P < 0.05) and 14% (P < 0.05) greater than in controls, respectively. REE and protein breakdown were correlated (r = 0.73, P < 0.05). The hormonal profile was normal in HIV-infected subjects with the exception of low urinary C-peptide and plasma reverse triiodothyronine. Plasma interleukin-6 and tumor necrosis factor-alpha were greater than in controls, but energy intake was 1.53 times the REE in the HIV-infected men. Thus, at the asymptomatic stage of HIV infection, increased protein turnover contributes to the increase in the REE. Moderate hyperphagia, which occurred despite increased levels of cytokines, in conjunction with increased protein synthesis maintains a normal body composition, without significant loss of lean body mass.