The frequency of Trp64Arg polymorphism of the beta3-adrenergic receptor gene in healthy and obese Hungarian children and its association with cardiovascular risk factors

OBJECTIVE: To estimate the frequency of Arg64 allele of the beta(3)-adrenergic receptor (3-BAR) gene in healthy (H) and obese (O) Hungarian children, and to look for possible associations between this polymorphism and some clinical and metabolic characteristics of obese children. PATIENTS/METHODS: In all, 147 healthy (male: 68) and 295 obese (male: 168) children were examined. The average age of the children in the two groups was 12.4+/-1.7 vs 12.6+/-3.2, respectively. Exon 1 of 3-BAR was amplified by polymerase chain reaction and the fragments were digested with BstN1. In obese children, oral glucose tolerance test was carried out and blood pressure (BP) was checked. RESULTS: The frequency of Trp64Arg polymorphism in normal and obese Hungarian children was similar (H vs O: n=14/9.5% vs n=35/11.8%). Obese children carrying the Arg64 allele (n=35, male: 23) were compared to randomly chosen, obese children without the Arg64 allele (n=35, male: 20). A significant difference was found between the body weight (81.2+/-23.2 vs 75.6+/-17.7 kg; mean+/-s.d.; P<0.01), body fat (38.8+/-3.9 vs 36.5+/-2.3%; mean+/-s.d.; P<0.05), mean fasting insulin levels (31.4+/-16.7 vs 16.9+/-7.6 microIU/ml; P<0.001) and mean systolic BP values (125.2+/-10.1 vs 114.5+/-8.3 mmHg; P<0.001) of the two obese groups. CONCLUSIONS: The frequency of Trp64Arg polymorphism was similar in Hungary as compared to other European countries. Although the prevalence of this polymorphism was similar in H and O children, the presence of Arg64 allele seems to be associated with increased adiposity, elevated systolic BP and higher fasting insulin levels.     

Energy requirements in the eighth decade of life

BACKGROUND: Knowledge of energy requirements among relatively healthy elderly is limited. OBJECTIVES: The objectives of the study were to measure total energy expenditure (TEE)-derived energy requirements in a biracial population of older adults without limitations to daily life and to test these empirical measures against national and international recommendations. DESIGN: TEE (measured by the doubly labeled water method), resting metabolic rate (RMR), activity-related energy expenditure (AEE), and body composition were measured in 288 persons aged 70-79 y selected from the Health, Aging, and Body Composition Study. RESULTS: TEE was lower in women (approximately 530 kcal/d; P < 0.0001) than in men because of the women's lower RMR and AEE. Fat-free mass explained the sex difference in RMR, but body weight failed to account for the women's lower AEE (approximately 1 kcal x kg(-1) x d(-1); P = 0.007). Blacks had lower TEE than did whites (approximately 100 kcal/d, P = 0.03), and that was explained by blacks' lower RMR. Physical activity level (TEE/RMR) did not differ significantly between sexes and races (1.70 +/- 0.23). The World Health Organization (WHO) recommendations overestimated TEE by 10 +/- 15% (P < 0.0001) in women but not in men, and the dietary reference intakes (DRIs) were accurate to 0 +/- 14% (P = 0.1). Both WHO and DRI recommendations are based on an underestimated physical activity level, and WHO recommendations are based on overestimated RMR. CONCLUSIONS: This study of well-functioning older adults confirms the racial difference in energy metabolism and supports the use of the 2002 DRIs. Because the DRIs and WHO recommendations underestimated PAL, new predictive equations of energy requirements are proposed.     

Physical activities and energy expenditures of institutionalized Japanese elderly women

The daily energy expenditure and physical activity index of institutionalized Japanese elderly women were measured. One hundred and thirteen Japanese elderly women (aged 79.5 -/+ 7.0 y) who live in institutions for the elderly and receive meal services participated voluntarily. A dietary survey, energy metabolic study, and time study were carried out over three consecutive days, and the basal metabolic rate (BMR) and energy expenditure by physical activity were measured. The intensity of daily physical activity was based on the physical activity index (PAI: total/basal energy expenditure). The mean BMR was 881 +/- 145 kcal/d (20.9 +/- 3.8 kcal/kg BW). The PAI in individuals ranged from 1.01 to 1.57, the mean value was 1.26 +/- 0.14, and 64% of the subjects examined showed a lower value than 1.3 of PAI. From these values, the mean total energy expenditure was calculated as 1,112 +/- 231 kcal/d (26.2 +/- 5.2 kcal/kg BW).     

Unexplained Disturbance in Body Weight Regulation Diagnostic Outcome Assessed by Doubly Labeled Water and Body Composition Analyses in Obese Patients Reporting Low Energy Intakes

Subjects Ten patients who had long-term disturbances in body weight regulation, were referred over a 3-year period for obesity evaluation, and reported low energy intakes (

Objective To ascertain whether these patients had a low energy expenditure and thus reduced energy requirement, and/or whether they were misreporting their energy intake.

Design Comparison of outcome measures in referred patients and in obese control patients who did not report low energy intakes and disturbances in body weight regulation.

Main outcome measures Low energy expenditure was evaluated with serum thyroid hormone levels, resting metabolic rate (RMR), thermic effect of food (TEF), and total energy expenditure (TEE) by doubly labeled water technique. Misreporting of energy intake was evaluated by comparing patients' self-reported energy intake with energy intake estimated by doubly labeled water and body composition analyses over a 14-day period.

Statistical analyses performed Low energy expenditure was considered present in a patient if RMR or TEE was more than 15% below predicted values according to results from the control group. Patient group TEF was compared with TEF results observed in the control group.

Results All patients had normal serum thyroid hormone levels. Eight patients had RMR and TEE values within 15% of predicted values and were substantially underreporting their energy intake. One patient had low TEE (−19%) and a normal RMR, a finding that implies a low level of physical activity. This patient also underreported energy intake as estimated by the doubly labeled water technique during the study (−38%). The 10th patient had a low RMR (−23.2%) and TEE (−25.0%), the mechanism of which was uncertain. This patient's reported food intake over the 14-day period was accurate but was less than her long-term intake over months or years as suggested by doubly labeled water TEE estimates. The TEF response in patients was not significantly different from that observed in the control group.

Conclusions Underreporting of energy intake from foods is a frequent finding in patients with disturbances in body weight regulation who are referred for obesity evaluation. Severe underreporting may be detectable by means' of screening measures available to most dietitians. Low energy expenditure, due either to physical inactivity or to metabolic factors, is also observed. Modern evaluation methods provide new insights into patients with weight regulatory disturbances and at the same time stimulate important new research questions. J Am Diet Assoc. 1995; 95:1393-1400.     

Metabolic differences in response to a high-fat vs. a high-carbohydrate diet

Energy expenditure was measured in a group of 7 subjects who received two isocaloric isonitrogenous diets for a period of 9-21 days with a 4-10-day break between diets. Diet 1 was a high-fat diet ( 83.5 +/- 3.6% of total energy). Diet 2 was a high carbohydrate diet ( 83.1 +/- 3.7% of total energy). Resting and postprandial resting metabolic rate were measured by open circuit indirect calorimetry 2-4 times during each metabolic period. Total energy expenditure (TEE) was measured by the doubly labeled water method over an 8-13-day period. The respiratory quotient was measured 2-4 hours after a meal during each metabolic period for the calculation of total energy expenditure by the doubly labeled water method. Levels of total T3 (TT3), T3 uptake, free thyroid index and T4 were measured at the end of each metabolic period. No significant changes in resting metabolic rate (RMR) were apparent on the two diets (1567 +/- 426 kcal/d high-fat diet and 1503 +/- 412 kcal/d high-carbohydrate diet n=7, p<0.15). Total energy expenditure measured in 5 subjects was significantly higher during the high-carbohydrate phase of the diet (2443 +/- 422 vs. 2078 +/- 482 kcal/d p<0.05). Activity estimated from TEE/RMR was greater on the high-carbohydrate diet but only approached statistical significance (p<0.06). Total T3 was significantly lower and free thyroid index and T3 uptake were significantly higher at the end of the high fat diet in comparison to the high-carbohydrate diet. These data suggest that individual tolerance to a high-fat diet varies considerably and may significantly lower TEE by changing levels of physical activity. The explanation for changes in thyroid hor. mone levels independent of changes in metabolic rate remains unclear.     

活动记录辅助加速度仪测量总能量消耗的初步研究

目的 用活动记录辅助加速度仪测量人体日常活动的能量消耗,为监测个体总能量消耗(TEE)提供简便易行的方法.方法 采用气体代谢法标定加速仪不同活动强度记录所对应的能量消耗;41名受试者连续佩戴加速度仪7 d,同时记录每日活动,间接估算每日总能量消耗.结果 加速仪测量TEE,男性(9761±866)kJ/d[(2332±207)kcal/d,休力活动水平(PAL)1.46±0.11],女性(7526±879)kJ/d[(1798±210)kcal/d,PAL 1.43±0.09];加速仪结合活动记录的测量结果为,男性(10573±804)kJ/d[(2526±192)kcal/d,PAL 1.58±0.10],女性(8191±737)kJ/d[(1957±176)kcal/d,PAL 1.56±0.08].结论 加速度仪配合活动记录所得TEE值在既往报道的范围之内,可以作为监测个体TEE和体力活动水平变化的简便方法.     

Comparison of thermic effects of constant and relative caloric loads in lean and obese men

Controversy regarding defective thermic effect of food (TEF) in obesity might be related to differences among studies in the caloric loads. To clarify further the role of blunted thermogenesis in obesity, responses to the same absolute caloric load (720 kcal) and a relative load, which was 35% of each subject's resting metabolic rate (RMR), were compared in 11 lean (L) and 11 obese (O) men. The relative load was slightly larger for O than L (752 +/- 27 vs 683 +/- 21 kcal; means +/- SEM, NS). TEF, calculated as 3-h postprandial minus fasting RMR, was greater for L than O for both the 720-kcal (69 +/- 4 vs 31 +/- 3 kcal/3 h, p less than 0.01) and relative loads (64 +/- 4 vs 37 +/- 3 kcal/3 h, p less than 0.01). For L, TEF was greater for the 720-kcal load than for the relative load whereas for O, TEF was greater for the relative than for the 720-kcal meal. However, expressed as a percent of the calories ingested, TEF for the absolute and relative meals was identical for each group, in both cases lower for O (4.2 +/- 0.4% vs. 4.7 +/- 0.3%) than for L (9.7 +/- 0.4% vs 9.3 +/- 0.8%); p less than 0.01. These results demonstrate the impact on thermogenesis of the basis on which the meal is dosed and provide further evidence for defective thermogenesis in obesity.     

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

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

Effect of β3-adrenergic receptor gene polymorphism on body weight change in middle-aged, overweight women

Objectives To examine the effects of β₃-adrenergic receptor gene polymorphism on body weight change during a weight reduction program for middle-aged, overweight women with careful consideration of their energy intake and expenditure. Methods Design: Intervention study of weight reduction for 12 weeks in a community setting. Subjects: Eighty overweight middle-aged women who completed the individualized lifestyle modification program. Measurements: β₃-adrenergic receptor gene polymorphism was identified by polymerase chain reaction and consecutive restriction fragment-length polymorphism analysis. Anthropometrical parameters, lifestyle factors, blood lipid and glucose levels, physical activity level and energy intake were measured before and at the end of the program. Results The numbers of subjects with the Trp64Trp, Trp64Arg, and Arg64Arg genotypes were 45, 30 and 5, respectively. Baseline characteristics among subjects with the 64Arg allele had significantly smaller decrease in body weight and energy intake than those without the 64Arg allele. The change of other clinical characteristics did not differ between the two groups. After adjusting for the %change of energy intake, the %change of body weight did not differ between the two groups. Conclusion The 64Arg allele of the β₃-AR gene is not likely to be the factor determining the difficulty in losing body weight in Japanese middle-aged, overweight women. Lifestyle factors, such as the decrease in energy intake, might mask the effect of the 64Arg allele on body weight loss. Specific considerations for the management of energy intake would be needed to promote body weight loss for those with the 64Arg allele.     

Comparison of body fat distribution and blood lipid profiles according to Trp64Arg polymorphism for the beta 3-adrenergic receptor gene in Korean middle-aged women

The aim of this study was to determine whether there was an association between body fat distribution, blood lipid profiles, and beta 3-adrenergic receptor gene polymorphism in Korean middle-aged women. Subjects were grouped according to BMI as obese (> or = 5 BMI, n = 95) or non-obese (BMI<25, n = 93). The Trp64Arg mutation of the beta 3-adrenergic receptor gene was detected by PCR-RFLP. Skinfold thickness, body circumference, intra-abdominal fat area by CT, and blood lipid profiles were also measured. Data were compared using ANOVA, Bonferroni t-test, and Chi-square. Significance for statistical analyses were set at p<0.05. In the obese group, 63.16% were Trp64Trp homozygotes and 36.84% were Trp64Arg heterozygotes, compared to 80.65% who were Trp64Trp homozygotes and 19.35% who were Trp64Arg heterozygotes in the non-obese group. These results indicated a significant (chi-square = 4.943, p<0.05) difference between the two groups. Frequency of the Arg64 allele in the obese group (16.84%) showed a significant (chi-square = 4.185, p<0.05) difference as compared to the non-obese group (9.68%). Skinfold thickness and body circumference of the Trp64Arg heterozygote group showed a consistent increase as compared to the Trp64Trp homozygote group. Visceral fat area and VSR of Trp64Arg heterozygote group showed a higher tendency than Trp64Trp homozygotes in the obese group, but these differences were not statistically significant. In conclusion, the Trp64Arg polymorphism of the beta 3-adrenergic receptor gene is associated with obesity in middle-aged Korean women, but it is difficult to suggest the prominent association of the Trp64Arg polymorphism of the beta 3-adrenergic receptor gene with prevalence of abdominal obesity or dyslipidemia in Korean middle-aged women.     

Carbohydrate malabsorption may increase daily energy requirements in infants

OBJECTIVE: Carbohydrate malabsorption in infants has been found to increase nutrient losses. However, the effect of this alteration on daily metabolic rate is unknown. We assessed daily metabolic rates in infants with asymptomatic carbohydrate malabsorption (ACM) after a single fruit juice load. METHODS: Sixteen healthy infants with ACM (63.3 +/- 5.6 cm, 7.5 +/- 1.0 kg, 5.6 +/- 0.8 mo, peak breath hydrogen [BH2] = 39.1 +/- 22.4 ppm) and 16 without ACM (64.3 +/- 3.9 cm, 7.8 +/- 1.0 kg, 5.0 +/- 0.8 mo, BH2 = 9.4 +/- 4.7 ppm), after a single fruit juice load, had 24-h energy expenditure (24-h EE; kcal x kg(-1) x d(-1)), resting (RMR; kcal x kg(-1) x d(-1)) and sleeping (SMR; kcal x kg(-1) x d(-1)) metabolic rates extrapolated from 3.5-h assessments in the Enhanced Metabolic Testing Activity Chamber. Furthermore, RMR was calculated with the World Health Organization (WHO), Schofield weight-based and weight- and height-based equations. Carbohydrate absorption was determined by BH2. Differences (P < 0.05) were determined by t test. RESULTS: All infants with ACM had greater (P < 0.05) extrapolated 24-h EE (91.2 +/- 24.8 versus 78.0 +/- 6.8) and RMR (71.8 +/- 15.2 versus 59.5 +/- 5.9). This represented an increase of 15-18.5%, respectively, in energy expenditures. Carbohydrate malabsorption was a significant determinant of EE, RMR, and SMR. However, the WHO (53.8 +/- 1.0 versus 54.1 +/- 0.9) and both Schofield equations (54.7 +/- 0.9 versus 54.9 +/- 1.0 and 50.6 +/- 7.5 versus 47.3 +/- 6.7) failed to detect any differences in RMR. There was a 20 percentile reduction in growth performance in infants with carbohydrate malabsorption. CONCLUSIONS: Infants with ACM following fruit juice ingestion may have increased daily energy expenditure leading to increased metabolic requirements.     

Comparison of methods for achieving 24-hour energy balance in a whole-room indirect calorimeter

OBJECTIVE: To evaluate and compare methods for achieving 24-hour energy balance in a whole-room indirect calorimeter. RESEARCH METHODS AND PROCEDURES: Twenty-four-hour energy expenditure (EE) for 34 healthy adults (16 women, 18 men) was measured in a calorimeter during a prestudy day and on a subsequent nonconsecutive assessment day (AD). Several methods for estimating EE on the AD using activity factors or regression equations with data available before the AD [anthropometrics, body composition, resting metabolic rate (RMR), sleeping metabolic rate (SMR) on prestudy day, 24-hour EE on prestudy day] were compared for predictive accuracy. RESULTS: Use of a 24-hour calorimeter stay gave the smallest mean absolute error (119 +/- 16 kcal/d) and smallest single maximum error (361 kcal/d). However, several other methods were only slightly, and not significantly, less accurate (e.g., mean absolute error = 131 +/- 17, 140 +/- 20, and 141 +/- 22 kcal/d and greatest error = 384, 370, and 593 kcal/d for anthropometric, RMR, and SMR regression equations, respectively). Fat-free mass alone and SMR with a simple activity factor were seen to be less accurate. DISCUSSION: Our results indicate that there may be some improvement in achieving 24-hour energy balance in a metabolic chamber by using a preceding 24-hour calorimeter stay; that only slightly less accurate predictions can be obtained using a combination of anthropometric, body composition, and/or RMR measurements; and that there is little or no advantage in using SMR from a previous overnight calorimeter stay.     

The Impact of Food Intake and Exercise on Energy Expenditure

Food intake and physical exercise affect two components of energy expenditure, resting metabolic rate (RMR) and the thermic effect of feeding (TEF). Classic studies of overfeeding and underfeeding clearly showed that caloric deficit and surfeit conditions alter RMR. Recent work on short-term overfeeding of monozygotic twins provides new evidence that genetic factors influence individual sensitivity to changes in RMR and TEF when caloric excess is present. Exercise affects energy expenditure during nonactive times; acute bouts of vigorous exercise may result in increased RMR, and this effect appears most pronounced in the first 12 h after exercise. Acute exercise may potentiate the thermic effects of food when they are taken together, and high levels of exercise training may increase RMR. Thus, physical exercise appears to play an important role in the regulation of energy balance by way of its direct energy cost and its influence on RMR and TEF.     

Energy balance in predialysis patients on a low-protein diet.

OBJECTIVE: To determine if energy intake on a low-protein diet (0.6 g protein/kg ideal body weight (ibw)/d) with 70% animal protein (Diet A) or 30% animal protein (Diet B) meets energy expenditure derived from measured resting energy expenditure and activity levels. DESIGN: Patients already on a conventional low-protein diet with 70% animal protein kept a 5-day weighed dietary intake, with a 3-day activity diary, and had their resting metabolic rate (RMR) measured. Patients then switched to a diet with 30% animal protein for a minimum of 2 weeks (range, 2 to 16 weeks) and repeated the weighed intake and RMR measurement. SETTING: Predialysis hospital outpatients. PATIENTS: Seven patients were recruited, 5 male. Mean age, 56 years (range, 43 to 78 years); mean serum creatinine 300 micromol/L (range, 180 to 560 micromol/L). INTERVENTION: Indirect calorimetry used to measure RMR. MAIN OUTCOME MEASURE: RMR compared with standard formulae and total energy expenditure compared with dietary intake. RESULTS: Mean RMR was 5.76 MJ/d (1,385 kcal/d) or 84.9 kJ/kg ibw/d (20.3 kcal/kg ibw/d); which was 108% to 113% of that predicted by standard formulae. Total energy expenditure (RMR plus activity) was 8.35 MJ/d (1,996 kcal/d) or 123.3 kJ/kg/d (29.5 kcal/kg ibw/d). Mean energy intake was 116.3 (27.8 kcal/kg ibw/d) on Diet A and 131.2 (31.4 kcal/kg ibw/d) on Diet B (P = .096) with 3 of the 7 patients meeting their energy expenditure on Diet A and 4 on Diet B. CONCLUSION: RMR of patients with chronic renal failure is within expected range for healthy individuals, and the activity of these relatively fit patients similar to healthy individuals with light to moderate activity. Energy intake on the low-protein diets failed to meet energy expenditure in 4 patients on Diet A and 3 patients on Diet B. Low energy intake may contribute to the development of malnutrition in some patients.     

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.     

Variability of measured resting metabolic rate

BACKGROUND: The necessity of a 12-h fast before resting metabolic rate (RMR) is measured is often a barrier to measuring RMR. OBJECTIVE: We compared RMR measurements obtained in the morning and afternoon and across repeated days to elucidate the magnitude and sources of variability. DESIGN: Healthy men (n = 12) and women (n = 25) aged 21-67 y, with body mass indexes (in kg/m(2)) ranging from 17 to 34 and body fat ranging from 6% to 54%, completed 4 RMR measurements. RMR measurements were made in the morning (after a 12-h fast and 12 h postexercise) and in the afternoon (after a 4-h fast and 12 h postexercise) on 2 separate days with the ventilated-hood technique. Body composition was assessed by dual-energy X-ray absorptiometry. RESULTS: Mean (+/- SE) afternoon RMR was significantly higher than morning RMR on both visit 1 (1593.5 +/- 35.6 compared with 1508.0 +/- 31.5 kcal/d; P = 0.001) and visit 2 (1602 +/- 29.3 compared with 1511.4 +/- 35.9 kcal/d; P = 0.001). The 2 morning measurements (r = 0.93) and the 2 afternoon measurements (r = 0.93) were highly correlated, and no significant differences between measurements were observed. The mean difference between the morning and afternoon measurements was 99.0 +/- 35.8 kcal/d (6%). CONCLUSIONS: Repeated morning and evening measurements of RMR were stable and highly correlated. Day-to-day measurements of RMR were not significantly different. RMR measured in the afternoon after a 4-h fast and exercise was approximately 100 kcal/d higher than RMR measured in the morning.     

Resting metabolic rate in chronic renal failure.

OBJECTIVE: A decrease in resting metabolic rate (RMR) in patients with chronic renal failure was assumed to occur because of the decreasing oxygen consumption of the kidneys, which in healthy subjects, accounts for 7.2% of RMR. Contrary to this assumption, RMR per body weight in end-stage renal disease was increased. DESIGN AND METHODS: To test the impact of chronic renal failure on the RMR, direct bedside calorimetry was performed on 51 outpatients (age, 53.2 +/- 13.9 y; creatinine clearance, 6.9 to 52 mL/min). Twenty two of 51 patients were examined repeatedly (at the start of the study, after 3 months, and after 6 months) during declining kidney function. RESULTS: In the total group, RMR per body weight (RMR/BW) was 100.0 +/- 4.96 kJ/kg/day and RMR per body surface area (RMR/BSA) was 4.582 +/- 0.181 kJ/min/1.73m(2). RMR/BW and RMR/BSA correlated significantly with creatinine clearance (n = 51, r = -.763, P <.001; n = 51, r = -.557, P <.001). In the follow-up group, creatinine clearance decreased from 27.5 +/- 9.5 mL/min initially, to 19.4 +/- 6.25 mL/min at 3 months, to 13.0 +/- 3.8 mL/min at 6 months (P <.001), while RMR/BW and RMR/BSA increased from 98.28 +/- 6.3, to 101.64 +/- 5.46, to 105.42 +/- 6.3 kJ/kg BW/d (P <.005), respectively, and 4.41 +/- 0.126, to 4.578 +/- 0.168, to 4.704 +/- 0.168 kJ/min/1.73 m(2) (P <.05), respectively. CONCLUSION: Taking into account the reduced oxygen consumption of the shrinking kidneys, the normal RMR suggests an increased energy expenditure per body cell mass. The raising RMR in deteriorating excretory kidney function reflects the increasing energy expenditure in progressive chronic renal failure.     

Components of total energy expenditure in healthy young women are not affected after 14 days of feeding with medium-versus long-chain triglycerides.

OBJECTIVE: To examine the effect of consumption of medium-chain triglycerides (MCT) vs. long-chain triglycerides (LCT) on total energy expenditure (TEE) and its components in young women during the second week of a 2-week feeding period. RESEARCH METHODS AND PROCEDURES: Twelve healthy lean women (age: 22.7+/-0.7 years, body mass index [BMI]: 21.5+/-0.8 kg/m2) were fed weight maintenance diets containing 15% of energy as protein, 45% as carbohydrate, and 40% as fat, 80% of which was treatment fat, for 2 weeks in a randomized cross-over design separated by a 2-week washout period. Dietary fat was composed of triglycerides containing either 26% medium-chain fatty acids (MCFA) and 74% long-chain fatty acids (LCFA), or 2% MCFA and 98% LCFA. Free-living TEE was measured from day 7 to 14 on each dietary treatment using doubly labeled water (DLW). Basal metabolic rate (BMR) and thermic effect of food (TEF) were measured on days 7 and 14 using respiratory gas exchange analysis (RGE) for 30 minutes and 330 minutes, respectively. Activity-induced energy expenditure (AIEE) was derived as the difference between TEE and the sum of BMR and TEF. RESULTS: The average TEE while consuming the MCT diet (2246+/-98 kcal/day) did not differ from that of the LCT diet (2186+/-138 kcal/day. BMR was significantly higher on the MCT diet on day 7 (1219+/-38 kcal/day vs. 1179+/-42 kcal/day), but not on day 14; there was no effect of diet on TEF. There were no differences in BMR, TEF, or AIEE between diets when expressed as percentages of TEE. On average, BMR, TEF, and AIEE represented 54.6%, 8.2%, and 37.2%, respectively, of TEE. DISCUSSION: Results suggest that between day 7 and day 14 feeding of MCT vs. LCT at these levels, TEE is not affected and that increases seen in energy expenditure following MCT feeding may be of short duration. Thus, compensatory mechanisms may exist which blunt the effect of MCT on energy components over the longer term.     

Effects of habitual physical activity on the resting metabolic rates and body compositions of women aged 35 to 50 years.

OBJECTIVE: To examine the effect habitual physical activity has on resting metabolic rate (RMR) and body composition (fat-free mass[FFM], fat mass, and percent body fat) in active compared to sedentary adult women. DESIGN: RMR was measured (by indirect calorimetry) twice after a 12-hour fast at the same point of the menstrual cycle and 48 hours after exercise. FFM, fat mass and percent body fat were measured using whole body air displacement plethysmography. Energy intake and expenditure were determined using 7-day weighed-food records and activity logs. SUBJECTS: Healthy, weight-stable premenopausal women aged 35 to 50 years classified as either active (approximately 9 hours per week of physical activity for 10 or more years) (n= 18) or sedentary (approximately 1 hour per week of physical activity) (n= 14). STATISTICAL ANALYSES: Analysis of covariance was used to investigate differences in mean RMR (kcal/day) between the groups adjusted for FFM, and independent t tests were used to determine differences in demographic, energy expenditure, and diet variables. RESULTS: Percent body fat and fat mass were lower (P<.0005) and RMR (adjusted for FFM) was significantly higher in the active women (P=.045) compared with sedentary controls. In the active and sedentary groups respectively, mean adjusted RMR was 1,510 kcal/day and 1,443 kcal/day, body fat was 18.9% and 28.8%, and fat mass was 11.1 kg and 18.8 kg. Groups were similar in body mass, FFM, body mass index, and age. Mean energy balance appeared to be more negative in the active group (P=.0059) due to significantly higher mean self-reported energy expenditures (P=.0001) and similar mean self-reported energy intakes (P=.52) compared with sedentary controls. These data indicate that active women who participate in habitual physical activity can maintain lower body fat and a higher RMR than sedentary controls with similar body mass, FFM, and body mass index. APPLICATIONS/CONCLUSIONS: This research supports and emphasizes the benefits of habitual physical activity in maintaining RMR and lower body fat levels in middle-aged women.     

Estimated energy expenditure and physical activity patterns of adolescent distance runners

The purpose of this study was to examine the estimated total energy expenditure (TEE) and physical activity patterns of adolescent distance runners. Twenty-eight (20 male, 8 female) adolescent distance runners self-reported their daily physical activity with the Bouchard 3-d diary. Mean values for TEE, 57.4 +/- 11.6 and 51.0 +/- 9.8 kcal x kg(-1) x d(-1), and activity energy expenditure (AEE), 26.7 +/- 10.4 and 21.0 +/- 8.8 kcal x kg(-1) x d(-1), when expressed per kilogram body mass were not significantly different between males and females, respectively (P = 0.18). When expressed in absolute terms, TEE, 3609 +/- 927 and 2467 +/- 426 kcal/d, and AEE, 1688 +/- 746 and 977 +/- 269 kcal/d, were significantly higher in males than in females, respectively. The results document the energy expenditure and self-reported physical activity of adolescent distance runners and might be used to address recommendations for adequate dietary energy requirements in this group, which in turn is important for energy balance in the context of normal growth, health, and physical performance.