Larger mass of high-metabolic-rate organs does not explain higher resting energy expenditure in children

BACKGROUND: Children have a high resting energy expenditure (REE) relative to their body weight. The decline in REE during growth may be due to changes in body composition or to changes in the metabolic rate of individual organs and tissues. OBJECTIVES: The goals were to quantify body-composition components in children at the organ-tissue level in vivo and to determine whether the observed masses 1) account for the elevated REE in children and 2) account, when combined with specific organ-tissue metabolic constants, for children's REE. DESIGN: This was a cross-sectional evaluation of 15 children (aged 9.3 +/- 1.7 y) and 13 young adults (aged 26.0 +/- 1.8 y) with body mass indexes (in kg/m(2)) < 30. Magnetic resonance imaging-derived in vivo measures of brain, liver, kidney, heart, skeletal muscle, and adipose tissue were acquired. REE was measured by indirect calorimetry (REE(m)). Previously published organ-tissue metabolic rate constants were used to calculate whole-body REE (REE(c)). RESULTS: The proportion of adipose-tissue-free mass as liver (3.7 +/- 0.5% compared with 3.1 +/- 0.5%; P < 0.01) and brain (6.2 +/- 1.2% compared with 3.3 +/- 0.9%; P < 0.001) was significantly greater in children than in young adults. The addition of brain and liver mass significantly improved the model but did not eliminate the role of age. REE(c) with published metabolic coefficients underestimated REE(m) (REE(c) = 3869 +/- 615 kJ/d; REE(m) = 5119 +/- 769 kJ/d; P < 0.001) in children. CONCLUSION: The decline in REE during growth is likely due to both a decrease in the proportion of some of the more metabolically active organs and tissues and changes in the metabolic rate of individual organs and tissues.     

Inflammation is associated with increased energy expenditure in patients with chronic kidney disease

BACKGROUND: Inflammation, a clinical condition observed in patients with chronic kidney disease (CKD), may be related to increased resting energy expenditure (REE). OBJECTIVES: The main objective was to investigate the relation between inflammation and REE in patients with CKD who are not undergoing dialysis. We also aimed to analyze whether a decrease in C-reactive protein (CRP) would result in a reduction in REE. DESIGN: This study enrolled 132 patients with CKD who were not undergoing dialysis, who had creatinine clearance from 5 to 65 mL.min(-1).1.73 m(-2), and who were 53.6 +/- 16 y old; 82 (62.1%) were men. Twenty-nine patients had clinical signs of infection. REE was measured by using indirect calorimetry, and inflammation was evaluated by using high-sensitivity CRP measurement. Patients were divided according to tertiles of CRP with the following intertertile ranges: first tertile, CRP < or = 0.14 mg/dL (n = 43); second tertile, CRP 0.15-0.59 mg/dL (n = 46); and third tertile, CRP > or = 0.60 mg/dL (n = 43). REE was measured before and after treatment in 10 patients who had inflammation or infection. RESULTS: After adjustment for age, sex, and lean body mass, the REE of the third (1395 kcal/d; P = 0.02) and second (1355 kcal/d; P = 0.04) tertiles was significantly higher than that of the first tertile (1286 kcal/d). In the multiple linear regression analysis (n = 132), the independent determinants of REE were lean body mass, CRP, and age (R2 = 0.55). After treatment of infection in a subgroup of 10 patients, it was observed that a significant reduction in CRP concentration was accompanied by a significant reduction of 174 +/- 165 kcal that accounted for 13% of the initial REE. CONCLUSION: This study showed that inflammation is associated with increased REE in patients with CKD.     

A cellular-level approach to predicting resting energy expenditure across the adult years

BACKGROUND: We previously derived a whole-body resting energy expenditure (REE) prediction model by using organ and tissue mass measured by magnetic resonance imaging combined with assumed stable, specific resting metabolic rates of individual organs and tissues. Although the model predicted REE well in young persons, it overpredicted REE by approximately 11% in elderly adults. This overprediction may occur because of a decline in the fraction of organs and tissues as cell mass with aging. OBJECTIVE: The aim of the present study was to develop a cellular-level REE prediction model that would be applicable across the adult age span. Specifically, we tested the hypothesis that REE can be predicted from a combination of organ and tissue mass, the specific resting metabolic rates of individual organs and tissues, and the cellular fraction of fat-free mass. DESIGN: Fifty-four healthy subjects aged 23-88 y had REE, organ and tissue mass, body cell mass, and fat-free mass measured by indirect calorimetry, magnetic resonance imaging, whole-body (40)K counting, and dual-energy X-ray absoptiometry, respectively. RESULTS: REE predicted by the cellular-level model was highly correlated with measured REE (r = 0.92, P < 0.001). The mean difference between measured REE (x+/- SD: 1487 +/- 294 kcal/d) and predicted REE (1501 +/- 300 kcal/d) for the whole group was not significant, and the difference between predicted and measured REE was not associated with age (r = 0.009, NS). CONCLUSION: The present approach establishes an REE-body composition link with the use of a model at the cellular level. The combination of 2 aging-related factors (ie, decline in both the mass and the cellular fraction of organs and tissues) may account for the lower REE observed in elderly adults.     

A paradoxical increase in resting energy expenditure in malnourished patients near death: the king penguin syndrome

BACKGROUND: The metabolic expression of extreme starvation on the verge of death is unknown in humans. OBJECTIVE: The objective was to compare the resting energy expenditure (REE) of 5 extremely malnourished dying patients [body mass index (in kg/m(2)): 9.77 +/- 0.1] with that of 16 less-malnourished anorexia nervosa (AN) patients. DESIGN: REE was measured by indirect calorimetry and body composition was measured by anthropometry and dual-frequency bioelectrical impedance analysis. Fasting serum insulin, thyroid hormone, and catecholamine concentrations were also determined. RESULTS: At the start of refeeding, REE was high in each of the 5 extremely malnourished dying patients, whereas it was low in the 16 AN patients (mean +/- SD: 5174 +/- 391 kJ/d compared with 3844 +/- 619 kJ/d; P < 0.05). The high REE value in the 5 extremely malnourished dying patients was associated with almost no fat mass (FM), high urinary nitrogen loss (16.4 +/- 2.9 g/d), low serum fatty acid concentrations (0.36 +/- 0.23 mmol/L), and low or normal serum insulin, thyroid hormone, and catecholamine concentrations. During the first 2-4 wk of refeeding, REE and nitrogen loss decreased, whereas fatty acid concentrations increased in each of the 4 surviving patients; REE and urinary nitrogen output increased in the 16 AN patients. CONCLUSION: In malnourished persons near death, there is an increase in REE and in protein catabolism. The reason for this increase is unknown but could relate to consumption of the last mobilizable muscle mass and to diseased cellular membranes.     

The age-related decline in resting energy expenditure in humans is due to the loss of fat-free mass and to alterations in its metabolically active components

There is conflicting evidence as to whether the age-related decline in resting energy expenditure (REE) can be attributed to i) absolute changes in fat-free mass (FFM), ii) alterations in the composition of FFM or iii) decreasing organ metabolic rates. This study directly addressed the first and second hypotheses by quantification of metabolically active components of FFM assuming constant tissue respiration rates to calculate REE (REEc). REE was measured (REEm) in 26 young (13 females, 13 males, age 22-31 y) and 26 elderly subjects (15 females, 11 males, age 60-82 y) by indirect calorimetry and detailed body composition analysis was obtained using bioelectrical impedance analysis (BIA), dual energy X-ray absorptiometry (DXA), and MRI. Specific organ metabolic rates were taken from the literature. REEm adjusted for differences in FFM was lower in older subjects than in younger control subjects (5.43 +/- 0.61 MJ/d compared with 6.37 +/- 0.48 MJ/d; P < 0.001). Skeletal muscle mass plus liver mass accounted for 86% and 48% of the variance in REE in young and elderly subjects, respectively. The difference between REEm and REEc was 0.03 +/- 0.40 MJ/d and -0.36 +/- 0.70 MJ/d in young and elderly subjects, respectively. In the elderly 58% of the difference in variance was attributed to heart mass. REEm - REEc was -1.40 +/- 0.44 MJ/d in subjects with hypertensive cardiac hypertrophy, i.e., heart mass > 500 g, suggesting a decrease in heart metabolic rate with increasing heart mass. Excluding five elderly subjects with cardiac hypertrophy resulted in agreement between REEm and REEc in the elderly (-0.10 +/- 0.48 MJ/d). We concluded that the age-related decline in REE is attributed to a reduction in FFM as well as in proportional changes in its metabolically active components. There is no evidence for a decreasing organ metabolic rate in healthy aging.     

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.     

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).     

Resting metabolic rate, body composition and aerobic fitness comparisons between active and sedentary 54-71 year old males.

OBJECTIVE: To test the hypothesis that 55-70 y old male longterm exercisers (LE) have higher resting metabolic rates (RMR) than longterm nonexercisers (LNE). DESIGN: A power analysis demonstrated that this cross-sectional study required 12 subjects per group to detect a 10% RMR difference (kJ x kg FFM(-1) x d(-1)) between the LE and LNE (power = 0.8;alpha = 0.05). SUBJECTS: Twelve LE (X +/- s.d.; 63.5+/-3.4 y; 1.75+/-0.06 m; 69.01+/-8.24 kg; 20.4+/-4.9 %BF) and 12 LNE (63.6+/-5.6 y; 1.72+/-0.07 m; 79.44 12.4 kg; 29.6 4.4 %BF) were recruited from advertisements placed in a newspaper and on university and community noticeboards. INTERVENTIONS: Measurements were conducted for: RMR using the Douglas bag technique; body composition via a four compartment model which is based on determination of body density, total body water and bone mineral mass; and aerobic fitness using a submaximal work test on a cycle ergometer. RESULTS: The LE (93.00+/-7.16 kJ x kg(-1) x d(-1)) registered a significantly greater (P = 0.04) RMR than the LNE (84.70+/-11.23 kJ x kg(-1) x d(-1)) when energy expenditure was expressed relative to body mass, but this difference disappeared (P = 0.55) when the data were corrected for the non-zero intercept of the graph of RMR (MJ/d) against body mass. ANCOVA with FFM as the covariate also indicated that the RMR (MJ/d) difference between the groups was not statistically significant (P = 0.28). The adjusted means for the LE and LNE were 6.39 and 6.62 MJ/d, respectively. CONCLUSIONS: There are no RMR (MJ/d) differences between LE and LNE 54-71 y old males when statistical control is exerted for the effect of FFM and the higher value of the former group for RMR normalised to body mass disappears when this ratio is corrected for statistical bias.     

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.     

Low physical activity reduces total energy expenditure in women with rheumatoid arthritis: implications for dietary intake recommendations

BACKGROUND: Rheumatoid arthritis (RA) causes cachexia, a metabolic response characterized by loss of muscle mass and elevated resting energy expenditure (REE). However, energy expenditure in physical activity in subjects with RA is lower than that in healthy subjects. It is not known which effect predominates in regulating total energy expenditure (TEE), and thus whether the dietary energy requirements of subjects with RA are higher or lower than those of healthy subjects. OBJECTIVE: Our objective was to determine TEE in women with RA by using the reference method of doubly labeled water ((2)H(2)(18)O). DESIGN: In this case-control study, we examined 20 women with RA and 20 healthy women who were matched for age and body mass index. RESULTS: The patients with RA were cachectic (their body cell mass was 14% lower than that of the controls, P < 0.001), but REE was not elevated, reflecting good disease control. Mean (+/- SD) TEE was 1344 kJ/d lower in the patients than in the controls (9133 +/- 1335 compared with 10 477 +/- 1992 kJ/d; P < 0.02). The energy expenditure in physical activity of the patients was 1034 kJ/d lower than that of the controls (P < 0.04), which accounted for 77% of the difference in TEE between the 2 groups. The physical activity level (TEE/REE) of the patients also tended to be lower than that of the controls (1.70 +/- 0.24 compared with 1.89 +/- 0.36; P < 0.07). CONCLUSION: A low physical activity level is the main determinant of lower-than-normal TEE, and thus energy requirements, in women with RA.     

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.     

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.     

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.     

Variations in the measurement of resting energy expenditure in children with cystic fibrosis

OBJECTIVE: To investigate in children with cystic fibrosis (CF) and children without CF: (1) the test-retest reproducibility of a 20 min resting energy expenditure (REE) measurement; and (2) the long-term reproducibility of REE measurements in children with CF using longitudinal data. DESIGN: Cross-sectional study and longitudinal cohort. SETTING: A tertiary referral paediatric hospital. SUBJECTS: A total of 31 (11 male, 20 female) children (aged 12.8+/-3.6 y) with CF and 32 (14 male, 18 female) healthy children without CF (aged 12.2+/-2.3 y) were enrolled in the short-term reproducibility study. Long-term REE measurement reproducibility was assessed in another 14 children (5 male, 9 female) with CF, comparing their initial REE measurement with a subsequent measurement 1-2 y later. METHODS: All children had measurements of height, weight, skinfold thickness and indirect calorimetry. RESULTS: There was no statistically significant difference in REE between repeated measurements in children with CF (mean+/-s.d., 6240+/-1280 and 6220+/-1315 kJ/24 h) and in the children without CF (6040+/-956 and 6015+/-943 kJ/24 h). For the children with CF, the intraclass correlation coefficient was 0.99 and for children without CF the intraclass correlation coefficient was 0.97. The measurement errors were 119 and 177 kJ, respectively. Approximately 80% of the variation in REE in the CF group and 70% in the group without CF was explained by fat-free mass (FFM). Analysis of the longitudinal CF data show there was no difference in REE between a child's first measurement (5140+/-1140 kJ) and their subsequent measurement (5460+/-1190 kJ), after adjustment for changes in body size between the measurements. CONCLUSION: This study has demonstrated that a short-term 20 min REE measurement is reproducible and therefore valid in children with CF and children without CF. These results also indicate that in children with CF, long-term REE measurements are reproducible.     

Protein consumption is an important predictor of lower limb bone mass in elderly women

BACKGROUND: The effect of protein intake on bone density is uncertain, and evidence exists for beneficial effects of both low and high protein intakes. OBJECTIVE: The objective was to study the relation between protein consumption and bone mass in elderly women with allowance for other lifestyle factors affecting bone metabolism. DESIGN: We conducted a cross-sectional and longitudinal study of a population-based sample of 1077 women aged 75 +/- 3 y. At baseline, protein consumption was measured with a food-frequency questionnaire, and bone mass and structure were measured by using quantitative ultrasound of the heel. One year later, hip bone mineral density (BMD) was measured by using dual-energy X-ray absorptiometry. RESULTS: Subjects consumed a mean (+/-SD) of 80.5 +/- 27.8 g protein/d (1.19 +/- 0.44 g protein/kg body wt). Regression analysis showed a positive correlation between protein intake and qualitative ultrasound of the heel and BMD after adjustment for age, body mass index, and other nutrients. The dose-response effect was best characterized by protein consumption expressed in tertiles, such that subjects in the lowest tertile (<66 g protein/d) had significantly lower qualitative ultrasound of the heel (1.3%) and hip BMD (2.6%) than did the subjects in the higher tertiles (>87 g protein/d). CONCLUSION: These data suggest that protein intakes for elderly women above current recommendations may be necessary to optimize bone mass.     

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.     

Development and cross-validation of a prediction equation for estimating resting energy expenditure in healthy African-American and European-American women

OBJECTIVE: To develop, validate, and cross-validate a formula for predicting resting energy expenditure (REE) in African-American and European-American women. DESIGN: A cross-sectional study of REE in women. Participants were randomly assigned to one of two groups. One group served to develop and validate a new equation for predicting REE while the second was used to cross-validate the prediction equation. The accuracy of the equation was compared to several existing formulae. SETTING: University metabolic laboratory, Memphis, TN, USA. SUBJECTS: Healthy, premenopausal African-American and European-American women between 18 and 39 y of age. The validation sample included 239 women (age: 28.4 y, wt: 70.7 kg, body mass index (BMI): 25.2 kg/m(2), REE: 5840 kJ/day), while the cross-validation sample consisted of 232 women (age: 27.5 y, wt: 70.7 kg, BMI: 25.2 kg/m(2), REE: 5784 kJ/day). RESULTS: The prediction equation derived from the current sample, which included adjustments for ethnicity, was the only formula that demonstrated a high level of accuracy for predicting REE in both African-American and European-American women. The mean difference between REE predicted from the new formula and measured REE was 28 kJ/day (s.d.=668) for European-American women and 142 kJ/day (s.d.=584) for African-American women. CONCLUSIONS: Previous equations for predicting energy needs may not be appropriate for both African-American and European-American women due to ethnic differences in REE. A new equation that makes adjustments in predicted REE based on ethnicity is recommended for determining energy needs in these groups (Predicted REE (kJ/day)=616.93-14.9 (AGE (y))+35.12 (WT (kg))+19.83 (HT (cm))-271.88 (ETHNICITY: 1=African American; 0=European American)). SPONSORSHIP: Support for this study was provided by Grant #HL53261 from the National Heart, Lung, and Blood Institute.     

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   

Total energy expenditure, body fatness, and physical activity in children aged 6-9 y

BACKGROUND: The recent worldwide increase in the prevalence of childhood obesity may be due in part to a decrease in children's physical activity levels. OBJECTIVE: The current study of children in the years just before puberty aimed to 1) measure total energy expenditure (TEE) by use of the doubly labeled water (DLW) method, 2) determine the proportion of TEE related to physical activity, 3) investigate the relations between measures of physical activity and body fatness, and 4) investigate possible sex differences in these relations. DESIGN: The DLW technique was used to measure TEE over 10 d in 106 healthy children (52 boys) aged 7.8 +/- 0.9 y (x +/- SD). Fat-free mass, and hence fat mass, was derived from the (18)O dilution space. Resting energy expenditure (REE) was calculated with use of the Schofield equations. Physical activity level was calculated as TEE/REE. RESULTS: Mean TEE in both boys (7871 +/- 1135 kJ/d) and girls (7512 +/- 1195 kJ/d) was significantly different (P < 0.0001) from FAO/WHO/UNU recommendations (13% and 9% lower, respectively). There was no significant difference in physical activity level between boys (1.69 +/- 0.22) and girls (1.71 +/- 0.23). In boys but not girls, physical activity level was inversely correlated with BMI (r = -0.37, P < 0.01), fat mass (r = -0.46, P < 0.005), and percentage of body fat (r = -0.50, P < 0.0001). CONCLUSIONS: In boys but not girls, percentage of body fat is inversely associated with physical activity level. Physical activity is one factor contributing to body fatness in boys, but additional factors may influence the size of the fat stores in girls.     

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.