Metabolic response to experimental overfeeding in lean and overweight healthy volunteers

Possible adaptive mechanisms that may defend against weight gain during periods of excessive energy intake were investigated by overfeeding six lean and three overweight young men by 50% above baseline requirements with a mixed diet for 42 d [6.2 +/- 1.9 MJ/d (mean +/- SD), or a total of 265 +/- 45 MJ]. Mean weight gain was 7.6 +/- 1.6 kg (58 +/- 18% fat). The energy cost of tissue deposition (28.7 +/- 4.4 MJ/kg) matched the theoretical cost (26.0 MJ/kg). Basal metabolic rate (BMR) increased by 0.9 +/- 0.4 MJ/d and daily energy expenditure assessed by whole-body calorimetry (CAL EE) increased by 1.8 +/- 0.5 MJ/d. Total free-living energy expenditure (TEE) measured by doubly labeled water increased by 1.4 +/- 2.0 MJ/d. Activity and thermogenesis (computed as CAL EE--BMR and TEE--BMR) increased by only 0.9 +/- 0.4 and 0.9 +/- 2.1 MJ/d, respectively. All outcomes were consistent with theoretical changes due to the increased fat-free mass, body weight, and energy intake. There was no evidence of any active energy-dissipating mechanisms.     

Energy requirements and physical activity in free-living older women and men: a doubly labeled water study

Determinants of daily energy needs and physical activity are unknown in free-living elderly. This study examined determinants of daily total energy expenditure (TEE) and free-living physical activity in older women (n = 51; age = 67 +/- 6 yr) and men (n = 48; age = 70 +/- 7 yr) by using doubly labeled water and indirect calorimetry. Using multiple-regression analyses, we predicted TEE by using anthropometric, physiological, and physical activity indexes. Data were collected on resting metabolic rate (RMR), body composition, peak oxygen consumption (VO2 peak), leisure time activity, and plasma thyroid hormone. Data adjusted for body composition were not different between older women and men, respectively (in kcal/day): TEE, 2,306 +/- 647 vs. 2,456 +/- 666; RMR, 1,463 +/- 244 vs. 1,378 +/- 249; and physical activity energy expenditure, 612 +/- 570 vs. 832 +/- 581. In a subgroup of 70 women and men, RMR and VO2 peak explained approximately two-thirds of the variance in TEE (R2 = 0.62; standard error of the estimate = +/-348 kcal/day). Crossvalidation of this equation in the remaining 29 women and men was successful, with no difference between predicted and measured TEE (2,364 +/- 398 and 2,406 +/- 571 kcal/day, respectively). The strongest predictors of physical activity energy expenditure (P < 0.05) for women and men were VO2 peak (r = 0.43), fat-free mass (r = 0.39), and body mass (r = 0.34). In summary, RMR and VO2 peak are important independent predictors of energy requirements in the elderly. Furthermore, cardiovascular fitness and fat-free mass are moderate predictors of physical activity in free-living elderly.     

Interaction of M1 and M2 isozymes pyruvate kinase from human tissues with phospholipids

This study aimed to measure energy intake (EI) and total energy expenditure (TEE) of asthmatic males and to validate diet history as a method of estimating their energy requirements. EI was assessed by dietary history and TEE by the heart-rate monitoring method in a group of asthmatic and nonasthmatic males. Resting energy expenditure (REE) adjusted for fat-free mass was higher in asthmatic than in nonasthmatic males (5,037 versus 4,839 kJ x day(-1), p<0.05). TEE (93+/-1.8 versus 8.4+/-1.4 MJ x day(-1), respectively; p=NS) and EI (9.2+/-15 versus 8.8+/-15 MJ x day(-1), respectively, p=NS) were not statistically different in asthmatic and nonasthmatic male. EI was not statistically different from TEE in both groups of males. Asthmatic males showed an acceptable agreement between TEE and EI at the individual level (range of agreement: -3.2 to 2.9 MJ x day(-1)), and a good agreement at the group level (95% confidence interval for the bias, - 1.1 to 0.8 MJ x day(-1)). Males with mild-to-moderate asthma have a higher metabolic activity per unit fat-free mass than nonasthmatic males. This increased requirement is apparently well compensated by an adequate energy intake. Diet history is a suitable method for estimating energy requirements in males with mild-to-moderate asthma.     

Daily energy expenditure in free-living conditions in obese and non-obese children: comparison of doubly labelled water (2H2(18)O) method and heart-rate monitoring

OBJECTIVE: To compare the heart-rate monitoring with the doubly labelled water (2H2(18)O) method to estimate total daily energy expenditure in obese and non-obese children. DESIGN: Cross sectional study of obese and normal weight children. SUBJECTS: 13 prepubertal children: six obese (4M, 2F, 9.1 +/- 1.5 years, 47.3 +/- 9.7 kg) and seven non-obese (3M, 4F, 9.3 +/- 0.6 years, 31.8 +/- 3.2 kg). MEASUREMENTS: Total daily energy expenditure was assessed by means of the doubly labelled water method (TEEDLW) and of heart-rate monitoring (TEEHR). RESULTS: TEEHR was significantly (P < 0.05) higher than TEEDLW in obese children (9.47 +/- 0.84 MJ/d vs 8.99 +/- 0.63 MJ/d) whereas it was not different in non-obese children (8.43 +/- 2.02 MJ/d vs 8.42 +/- 2.30 MJ/d, P = NS). The difference of TEE assessed by HR monitoring in the obese group averaged 6.2 +/- 4.7%. At the individual level, the degree of agreement (difference between TEEHR and TEEDLW +/- 2s.d.) was low both in obese (-0.36, 1.32 MJ/d) and in non-obese children (-1.30, 1.34 MJ/d). At the group level, the agreement between the two methods was good in nonobese children (95% c.i. for the bias:-0.59, 0.63 MJ/d) but not in obese children (0.04, 0.92 MJ/d). Duration of sleep and energy expenditure during resting and physical activity were not significantly different in the two groups. Patterns of heart-rate (or derived energy expenditure) during the day-time were similar in obese and non-obese children. CONCLUSION: The HR monitoring technique provides an estimation of TEE close to that assessed by the DLW method in non-obese prepubertal children. In comparison with DLW, the HR monitoring method yields a greater TEE value in obese children.     

Direct measurement of the energy expenditure of physical activity in preterm infants

The energy cost of physical activity (EEA) has been estimated to account for 5-17% of total energy expenditure (TEE) in neonates. To directly measure EEA, a force plate was developed and validated to measure work outputs ranging from 0.3 to 40 kcal . kg-1 . day-1. By use of this force plate plus indirect calorimetry, TEE and EEA were measured and correlated with five activity states in 24 infants with gestational age of 31.6 +/- 0.5 (SE) wk and postnatal age of 24.8 +/- 3.7 days. TEE and EEA were 69.2 +/- 1.5 and 2.4 +/- 0.2 kcal . kg-1 . day-1, respectively. EEA per state was 0.5 +/- 0.0 (quiet sleep), 2.4 +/- 0.2 (active sleep), 2.8 +/- 0.4 (quiet awake), 7.5 +/- 0.8 (active awake), and 15.1 +/- 2.3 (crying) kcal . kg-1 . day-1. This provides the first direct measurement of the contribution of physical activity to TEE in preterm infants and will enable measurement of caloric expenditure from muscle activity in various disease conditions and development of nursing strategies to minimize unnecessary energy losses.     

Energy expenditure and net substrate utilization in men ingesting usual and high amounts of nonstarch polysaccharide

BACKGROUND: Diets intrinsically high in nonstarch polysaccharides (NSPs) are frequently advised for body weight regulation and health, but the consequences for energy expenditure and fuel selection are undetermined. OBJECTIVE: We determined whether energy expenditure and fuel selection differ when men consume a diet intrinsically higher in NSP than a usual mixed diet. DESIGN: A randomized crossover design was used in which 12 healthy men were fed a maintenance diet for approximately 3 wk in a metabolic suite. By judicial choice of food exchanges, the usual- and high-NSP diets were similar in protein, fat, and carbohydrate contents. Twenty-four-hour, indirect, open-circuit calorimetry was performed, including measurements of total hydrogen gas and methane. Participants were weight stable (within 2 kg for 3 wk), entered an 11-m3 calorimetry chamber for 36 h with measurements taken in the last 24 h, and underwent a strictly controlled program of moderate physical activity (1.3 x basal metabolic rate). RESULTS: The mean total 24-h energy expenditure and percentages from protein, fat, and carbohydrate metabolism were 10 MJ/d and 16%, 35%, and 48%, respectively. Differences (mean+/-SEM) between the 2 diets were only -0.005+/-0.130 MJ/d, -0.3+/-1.3%, -0.2+/-2.0%, and 0.6+/-2.2%, respectively, and were nonsignificant (P> 0.2). CONCLUSIONS: There was no thermogenic response to the high-NSP diet, which would be advantageous for body weight control, and no short-term influence on body composition, as may be judged from a lack of change in protein, fat, or carbohydrate metabolism.     

Synchronous direct gradient layer and indirect room calorimetry

A dual direct/indirect room-sized calorimeter is used at the Beltsville Human Nutrition Research Center to measure heat emission and energy expenditure in humans. Because the response times of a gradient layer direct calorimeter and an indirect calorimeter are not equivalent, the respective rate of heat emission and energy expenditure cannot be directly compared. A system of equations has been developed and tested that can correct the respective outputs of the direct gradient layer calorimeter and indirect calorimeter for delays due to the response times of the measurement systems. Performance tests using alcohol combustion to simulate a human subject indicate accurate measurements of heat production from indirect (99.9 +/- 0.4%), indirect corrected for response time (99.9 +/- 0.5%), direct (99.9 +/- 0.8%), and direct corrected for response time (99.9 +/- 0.8%) calorimetry systems. Results from 24-h measurements in 10 subjects indicate that corrected heat emission is equivalent to (99.8 +/- 2.0%) corrected energy expenditure. However, heat emission measured during sleep was significantly greater (14%) than energy expenditure, suggesting a change in the energy stored as heat in the body. This difference was reversed during the day. These results illustrate how the simultaneous measurement of heat emission and energy expenditure provides insights into heat regulation.     

Magnetic resonance imaging of articular cartilage: ex vivo study on normal cartilage correlated with magnetic resonance microscopy

PURPOSE: The purpose of this study was to determine the effects of a school-based, low-volume strength training program on energy expenditure, strength, and physical fitness in obese prepubertal girls. METHODS: A longitudinal, 5-month strength training exercise program was undertaken by healthy, obese (> 95th percentile weight-for-height, N = 11) girls age 7-10 yr. The following were measured: strength by the one-repetition maximum test; fitness (VO2peak) by a treadmill exercise test; resting metabolic rate (RMR), 24-h sedentary energy expenditure (SEE), and sleeping metabolic rate (SMR) by room respiration calorimetry; and total energy expenditure (TEE) by the doubly labeled water method. Physical activity energy expenditure (AEE) was calculated as TEE-(RMR + 0.1.TEE) and physical activity level (PAL) as TEE/RMR. An age-matched, nonoverweight control group was measured for (VO2peak) and RMR over the same time period. RESULTS: Strength increased by 19.6 and 20.0% in the upper and lower body (P < 0.01), respectively. (VO2peak) (mL.min-1) increased in both groups over time (P < 0.05), but not when covaried for fat-free mass (FFM) or weight. After adjusting for FFM or weight, RMR did not change, but SMR and 24-h SEE decreased significantly in the exercise group. There were no changes in nonprotein respiratory quotient or substrate oxidation. No changes in TEE, AEE, and PAL occurred, either unadjusted or adjusted for FFM or weight. CONCLUSION: This long-term, school-based, low-volume strength training program favorably increases strength in obese prepubertal girls but does not increase their daily energy expenditure.     

Associations between blood pressure and dietary intake and urinary excretion of electrolytes in a Chinese population

OBJECTIVE: The effect of age on energy expenditure was studied. DESIGN: Case-control study. SETTING: Respiration chamber at the University of Maastricht. SUBJECTS: Thirteen young men (27 +/- 4 years) and ten elderly men (74 +/- 5 years), were recruited with advertisements in local media. METHODS: In a 36 h experiment, 24 h energy expenditure (EE), sleeping metabolic rate (SMR), diet-induced thermogenesis (DIT) and energy expenditure of physical activity (EEact) were measured while subjects performed an activity protocol in a respiration chamber under strictly controlled conditions. RESULTS: SMR as a function of fat-free mass (FFM) was not different between both age groups. 24 h EE during a standardized activity protocol was significantly higher for the young men (young men: 12.85 +/- 1.53 MJ/d; elderly men: 10.90 +/- 1.12 MJ/d; P = 0.011). The DIT expressed as MJ/d was significantly higher for the young subjects but similar when expressed as percentage of energy intake (young men: 13.10 +/- 5.44%; elderly men: 9.88 +/- 3.86%). The resulting figure for EEact (24 h EE--SME--DIT) was the same for young and elderly men (young men: 3.11 +/- 0.71 MJ/d; elderly men: 3.05 +/- 0.64 MJ/d). CONCLUSION: The results indicate that mean energy costs for low intensity daily activities (some daily household activities and a bench stepping exercise) were the same for young and elderly men.     

Total and resting energy expenditure in obese women reduced to ideal body weight

Obesity could be due to excess energy intake or decreased energy expenditure (EE). To evaluate this, we studied 18 obese females (148 +/- 8% of ideal body weight [IBW], mean +/- SD) before and after achieving and stabilizing at IBW for at least 2 mo and a control group of 14 never obese females (< 110% of IBW or < 30% fat). In the obese, reduced obese, and never obese groups, the percent of body fat was 41 +/- 4%, 27 +/- 4%, and 25 +/- 3%; total energy expenditure (TEE) was 2704 +/- 449, 2473 +/- 495, and 2259 +/- 192 kcal/24 h; while resting metabolic rate was 1496 +/- 169, 1317 +/- 159, and 1341 +/- 103 kcal/24 h, respectively. 15 obese subjects who withdrew from the study had a mean initial body composition and EE similar to the subjects who were successful in achieving IBW. In 10 subjects followed for at least one year after stabilizing at IBW there was no significant relationship between the deviation from predicted TEE at IBW and weight regain. These studies indicate that, in a genetically heterogeneous female population, neither the propensity to become obese nor to maintain the obese state are due to an inherent metabolic abnormality characterized by a low EE.     

Seasonal weight loss and metabolic adaptation in rural Beninese women: the relationship with body mass index

A large variation in seasonal weight loss between individuals exists in rural communities in developing countries. Therefore, it was investigated whether some individuals show a metabolic adaptation and, through that, prevent large body-weight losses during the preharvest season. Basal metabolic rate (BMR), energy intake and physical activity level (PAL) of rural Beninese women were measured in three seasons. Groups of subjects were: women with a body mass index (BMI) < 18 (n 18), and a BMI > 23 (n 16), and women who had shown small (n 18) and large (n 15) preharvest weight loss. All groups of subjects decreased energy intake during the preharvest season by 0.66-1.09 MJ/d. PAL did not show significant seasonal changes in any of the four groups. Only subjects with a BMI < 18 decreased BMR during the preharvest season with 2.9 (SD 6.7) J/kg per min (P < 0.05), with a decrease of 0.8 (SD 1.4) kg (P < 0.05) in body weight. In very thin women with a BMI < 17 (n 5) BMR expressed per unit body weight decreased even more during the preharvest season (by 12%).     

Energy metabolism in sedentary and active 49- to 70-yr-old women

This study examined differences between long-term exercising (LE) and long-term nonexercising (LNE) women [n = 24; age 56.4 +/- 6.2 (SD) yr] for resting metabolic rate (RMR) and energy expenditure in the free-living state by using doubly labeled water (DLW). There was a statistically significant difference (P = 0.0002) between the 12 LE (94.85 +/- 8.44 kJ . kg-1 . day-1) and 12 LNE (81.16 +/- 6.62 kJ . kg-1 . day-1) for RMR, but this difference was only marginally significant (P = 0.06) when the data (MJ/day) were subjected to an analysis of covariance with fat-free mass as the covariate. The DLW data indicated that the eight most active LE (12.99 +/- 3.58 MJ/day) expended significantly (P = 0.01) more energy than did the eight least active LNE (9.30 +/- 1.15 MJ/day). Energy expenditures ranged from 7.64 to 18.15 MJ/day, but there was no difference (P = 0.96) between the LE and LNE in energy expenditure during activity that was not designed to either improve or maintain fitness. These cross-sectional data on 49- to 70-yr-old women therefore suggest that 1) aerobic-type training results in a greater RMR per unit of body mass and also when statistical control is exerted for the effect of the metabolically active fat-free mass, 2) there is a large range in the energy intake necessary to maintain energy balance, and 3) aerobic training does not result in a compensatory reduction in energy expenditure during the remainder of the day.     

Effects of wine on plasma fibrinolytic and coagulation systems

Energy expenditure was estimated using the doubly-labelled water (DLW) method in summer in five free-living adult, non-pregnant, non-lactating, red deer (Cervus elaphus) hinds (weight 107.3 (SE 0.9) kg; age 6 (SE 1) years) on lowland pasture under typical farming conditions. Climatic conditions were monitored throughout the experiment. Errors due to 2H losses in CH4 and faeces were calculated from previous estimates of stoichiometries. CH4 production, fractionated water loss, urinary N and O2 consumption were estimated using an iterative approach. The water flux (rH2O) in these animals consuming only fresh grass was 12 (SE 0.5) kg/d, the CO2 production (rCO2) was 1271 (SE 40) litres/d and the mean energy expenditure was 25 (SE 0.8) MJ/d. There were no significant differences in the isotope distribution spaces and flux rates, rH2O, rCO2 or energy expenditure using the multi-point or two-point approaches to calculation. The DLW-derived energy expenditure of 25 MJ/d is approximately 20% higher than the recommended intake of 21 MJ/d for adult hinds kept outdoors (Adam, 1986) and, at 757 kJ/kg0.75 per d, one third higher than the value of 570 kJ/kg0.75 per d for stags penned indoors (Key et al. 1984).     

Energy and water metabolism, body composition, and hormonal changes induced by 42 days of enforced inactivity and simulated weightlessness

Inactivity causes profound deleterious changes. We investigated in eight healthy men the impact of a 42-day head-down bed rest (HDBR) on energy and water metabolism and their interrelationships with body composition (BC) and catabolic and anabolic hormones. Total energy expenditure (TEE), total body water, water turnover, and metabolic water formation were assessed by the doubly labeled water method 15 days before and for the last 15 days of HDBR. Resting energy expenditure was determined by indirect calorimetry, and BC was determined by dual energy x-ray absorptiometry. Urinary excretion of cortisol, GH, normetanephrine, metanephrine, urea, and creatinine were measured daily. HDBR resulted in significant reductions in body weight (2%), total body water (5%), metabolic water (17%), and lean body mass (LBM; 4%), but fat mass and water turnover did not change. Segmental BC showed a decreased LBM in legs and trunk, whereas fat mass increased, no significant changes were noted in the arms. The hydration of LBM was unchanged. TEE and energy intake decreased significantly (20% and 13%), whereas resting energy expenditure was maintained. Expenditure for physical activity dropped by 39%. Subjects were in energy balance during HDBR, whereas it was negative during the control period (-1.5 MJ/day). There were decreases in urinary normetanephrine (23%) and metanephrine (23%), but urinary cortisol (28%; weeks 2 and 3), GH (75%; weeks 2-4), and urea (15%; weeks 3 and 4) increased. It was concluded that during prolonged HDBR no relevant modifications in water metabolism were triggered. BC changes occurred in the nonexercised body segments, and the reduction in TEE was due to inactivity, not to LBM loss. Moreover, body weight alone does not accurately reflect the subject's energy state, and energy balance alone could not explain the body weight loss, which involves a transient metabolic stress.     

Energy expenditure of a noncontact boxing training session compared with submaximal treadmill running

The aim of this study was to determine the energy expenditure of a 1-h noncontact boxing training session and to compare these results with the energy expenditure of a more conventional recreational activity such as running. Eight healthy males, accustomed to noncontact boxing training, were recruited for the study. Subjects underwent three tests: (i) a boxing training session in the laboratory during which energy expenditure was measured continuously using indirect calorimetry (BOXL), (ii) a boxing training session in a boxing studio during which heart rate was measured continuously (BOXS), and (iii) an incremental running test on the treadmill during which energy expenditure was measured continuously. The energy expenditure during 60 min of BOXL ranged between 2519 and 3079 kJ (2821 +/- 190 kJ). Seven of the 8 subjects had higher heart rates during BOXL compared with those during BOXS, suggesting that the subjects exercised at a slightly higher intensity during BOXL, possibly because of the "one on one" supervision. A typical boxing training session lasting 60 min causes a person to expend 2821 +/- 190 kJ x h(-1), the same amount of energy as someone running about 9 km in 60 min on the treadmill.     

Isolation and characterization of pectin methylesterase from papaya

To estimate energy expenditure (EE) in elderly subjects, more age-specific data are required on energy costs of standardized activities. EE was assessed by using indirect calorimetry in 28 women aged 72 +/- 4 y (mean +/- SD) and in 29 middle-aged women (42 +/- 1 y) at rest (resting metabolic rate; RMR) and during sitting, sitting with standardized arm activity, and walking on a treadmill at 3 km/h. RMR and EE during sitting, and sitting with standardized arm activity did not differ significantly between the groups, although EE expressed as a ratio of arm activity to RMR (physical activity ratio, PAR) tended to be higher in the elderly subjects. Walking EE was significantly higher in the elderly women (16.4 +/- 4.0 kJ/min) than in the middle-aged women (12.7 +/- 2.3 kJ/min), also when expressed as PAR. It is suggested that elderly women walk less efficiently. Because PARs are frequently used to estimate daily EE, it is important to note that additional age-specific data might be required.     

Effect of dietary manipulation on substrate flux and energy balance in obese women taking the appetite suppressant dexfenfluramine

BACKGROUND: Studies in lean men show poor regulation of energy (EB) and fat balance (FB) during manipulation of dietary ratios of fat to carbohydrate. High-fat (HF), high-energy diets cause hyperphagia and a positive EB and FB. OBJECTIVE: The protocol was designed to measure substrate flux and EB in obese women taking dexfenfluramine (DF) or placebo (PL) during an HF (50% of energy) or low-fat (25% of energy; LF) diet. We hypothesized that alterations in dietary fat would not be regulated and would lead to a positive EB and FB. DESIGN: The study was double-blind, randomized, and placebo-controlled, with 4 treatments (LF/DF, HF/DF, LF/PL, and HF/PL) and a crossover. Five days of continuous, whole-body calorimetry measurements were made in 6 subjects after 8 d of home DF/PL treatment. Macronutrient balance and EB were measured within the chamber as the cumulative difference between ad libitum intake and oxidation. RESULTS: The HF diet increased energy (HF, 10.50 MJ/d; LF, 8.13 MJ/d; P < 0.0001) and fat intakes (HF, 5.34 MJ/d; LF, 2.06 MJ/d; P < 0.0001), leading to a positive EB (delta = 2.37 MJ/d) and FB (delta = 2.31 MJ/d). DF reduced energy (DF, 8.96 MJ/d; PL, 9.66 MJ/d; P < 0.01) and macronutrient intakes, but did not increase energy expenditure (delta = -0.31 MJ/d; P < 0.01), or 24-h fat oxidation (delta = 0.03 MJ/d; P = 0.46). CONCLUSIONS: EB and FB are poorly regulated with HF, energy-dense diets in obese women, which leads to fat deposition and weight gain.     

Three months of abstinence from alcohol normalizes energy expenditure and substrate oxidation in alcoholics: a longitudinal study

OBJECTIVE: The aim of this study was to evaluate the energy expenditure, substrate oxidation, and body composition in alcoholics during addiction and after several months of abstinence. METHODS: A total of 32 alcoholics without liver cirrhosis and malabsorption were consecutively recruited. A total of 55 social drinkers, matched for gender and height, were studied as a control group. Anthropometry and bioimpedance analysis were performed to assess body composition, and indirect calorimetry was used to measure basal metabolic rate (BMR) and substrate oxidation. Total abstinence was then achieved in 15 subjects. At 1, 2, 3, and 6 months of abstinence, the metabolic variables and the energy intake were re-examined. RESULTS: At enrollment (T0) alcoholics compared to controls showed a significant decrease in body mass index (22.2+/-2.71 vs 23.6+/-1.3 kg/m2; p < 0.05), fat mass (14.1+/-4.5 vs 16.7+/-3.3 kg; p < 0.01), an increased BMR normalized by fat-free mass (34.5+/-3.7 vs 32.1+/-2.01 kcal/kg/day; p < 0.01), a lower nonprotein respiratory quotient (npRQ: 0.76+/-0.03 vs 0.83+/-0.03; p < 0.001), with a consequently higher lipid oxidation (0.08+/-0.02 vs 0.04+/-0.02 g/min; p < 0.01), and a lower carbohydrate oxidation (0.05+/-0.02 vs 0.10+/-0.03 g/min; p < 0.01). Although at 1 and 2 months of abstinence the metabolic parameters had improved, only after 3 months of abstinence did alcoholics show values of body mass index (23.2+/-2.6 kg/ m2), fat mass (17.0+/-5.34 kg), BMR/fat-free mass (33.1+/-2.78 kcal/kg/day), npRQ (0.82+/-0.02), lipid oxidation (0.05+/-0.03 g/min) and carbohydrate oxidation (0.11+/-0.04 g/min) comparable to those of controls; these values remained constant at 6 months. CONCLUSION: Three months of abstinence from alcohol could represent the minimum time necessary to obtain a normalization of the metabolic variables considered and of the nutritional status for these patients, probably related to a regression of the functional alterations of the microsomal ethanol oxidizing system and of mitochondria secondary to chronic ethanol abuse.     

Role of fiberoptic bronchoscopy in conjunction with the use of double-lumen tubes for thoracic anesthesia: a prospective study

Twenty-four-hour energy expenditure (EE) and substrate oxidation (respiratory chamber), and whole-body glucose uptake and oxidation rates (euglycemic hyperinsulinemic clamp [EHC] and indirect calorimetry) were measured in 10 male patients with posthepatitis, Child B cirrhosis, and 8 healthy male controls matched for age, body size, and body composition. Twenty-four-hour EE was higher in cirrhotic patients than in controls (8,567 +/- 764 vs. 6,825 +/- 507 kJ/d; P < .001). Resting energy expenditure (REE) was also higher in cirrhotic patients than in controls (7,881 +/- 1,125 vs. 5,868 +/- 489 kJ/d; P < .01). Twenty-four-hour respiratory quotient (RQ) (trend) and fasting RQ (0.76 +/- 0.05 vs. 0.82 +/- 0.04; P < .05) were lower in cirrhotic patients than in controls, reflecting higher lipid oxidation rates in the former group. Whole-body glucose uptake was markedly reduced in cirrhotic patients when compared with controls (22.4 +/- 3.2 vs. 44.5 +/- 7.6 mmol/kg/min; P < .001). Carbohydrate oxidation rates, computed during the last 40 minutes of the clamp, were 8.5 +/- 1.1 mmol/kg/min in cirrhotic patients and 22.6 +/- 6.1 mmol/kg/min in controls (P < .001). Nonoxidative glucose disposal was 13.9 +/- 2.5 mmol/kg/min in cirrhotic patients and 22.0 +/- 5.5 mmol/kg/min in normal controls (P < .01). In conclusion, our data indicate that patients with Child B cirrhosis who still maintain a nutritional status (i.e., body composition) comparable with healthy controls are characterized by a cluster of metabolic defects that include hypermetabolism, increased lipid utilization, and insulin resistance. This suggests that the above metabolic syndrome precedes and probably leads to malnutrition in the natural history of the liver disease. In fact, in spite of the absence of a significant difference in caloric intake between cirrhotic patients and normal controls, the elevated 24-hour EE might allow for a relevant weight loss in cirrhotic patients, because, with time, the differences may be cumulative. However, whether this hypermetabolism can lead to a real weight loss remains to be evaluated in a longitudinal study.     

Differences in resting energy expenditure in prepubertal black children and white children

OBJECTIVE: To evaluate differences in resting energy expenditure (REE) of black and white prepubertal children. SUBJECTS: The study subjects were 34 prepubertal children 5 to 12 years of age and weighing 90% to 206% ideal body weight. Girls represented 59% of the study subjects; 44% were white children and 56% were black children. METHODS: Fat-free mass (FFM), fat mass, and the percentage of body fat were determined by total body electrical conductivity. Fasting REE was measured by open-circuit indirect calorimetry. RESULTS: Although weight, height, FFM, fat mass, percentage of body fat, and age were similar between the ethnic groups (black vs. white children), the black subjects had a significantly lower REE (1312 +/- 38 kcal/day) compared with the white subjects (1524 +/- 43 kcal/day) after adjusting for age, gender, weight, FFM, and fat mass. Fat-free mass and ethnic group were the only significant predictors of REE (R2 = 0.70). CONCLUSION: Resting energy expenditure is significantly higher in this sample of white children compared with the black children after adjusting for body size and composition. Both FFM and ethnic background were significant determinants of REE in prepubertal children.