Low plasma leptin concentration and low rates of fat oxidation in weight-stable post-obese subjects

OBJECTIVE: A low resting metabolic rate for a given body size and composition, a low rate of fat oxidation, low levels of physical activity, and low plasma leptin concentrations are all risk factors for body weight gain. The aim of the present investigation was to compare resting metabolic rate (RMR), respiratory quotient (RQ), levels of physical activity, and plasma leptin concentrations in eight post-obese adults (2 males and 6 females; 48.9 +/- 12.2 years; body mass index [BMI]: 24.5 +/- 1.0 kg/m2; body fat 33 +/- 5%; mean +/- SD) who lost 27.1 +/- 21.3 kg (16 to 79 kg) and had maintained this weight loss for > or =2 months (2 to 9 months) to eight age- and BMI-matched control never-obese subjects (1 male and 7 females; 49.1 +/- 5.2 years; BMI 24.4 +/- 1.0 kg/m2; body fat 33 +/- 7%). RESEARCH METHODS AND PROCEDURES: Following 3 days of weight maintenance diet (50% carbohydrate and 30% fat), RMR and RQ were measured after a 10-hour fast using indirect calorimetry and plasma leptin concentrations were measured using radioimmunoassay. Levels of physical activity were estimated using an accelerometer over a 48-hour period in free living conditions. RESULTS: After adjustment for fat mass and fat-free mass, post-obese subjects had, compared with controls, similar levels of physical activity (4185 +/- 205 vs. 4295 +/- 204 counts) and similar RMR (1383 +/- 268 vs. 1430 +/- 104 kcal/day) but higher RQ (0.86 +/- 0.04 vs. 0.81 +/- 0.03, p < 0.05). Leptin concentration correlated positively with percent body fat (r = 0.57, p < 0.05) and, after adjusting for fat mass and fat-free mass, was lower in post-obese than in control subjects (4.5 +/- 2.1 vs. 11.6 +/- 7.9 ng/mL, p < 0.05). DISCUSSION: The low fat oxidation and low plasma leptin concentrations observed in post-obese individuals may, in part, explain their propensity to relapse.     

The effects of a 20-week exercise training program on resting metabolic rate in previously sedentary, moderately obese women

The present study was designed to investigate the effects of exercise training on resting metabolic rate (RMR) in moderately obese women. It was hypothesized that exercise training would increase resting metabolic rate. Nineteen previously sedentary, moderately obese women (age = 38.0 +/- 0.9 years, percent body fat = 37.5 +/- 0.8) trained for 20 weeks using either resistance training (RT) or a combination of resistance training and walking (RT/W). The high intensity resistance-training program was designed to increase strength and fat-free mass and the walking program to increase aerobic capacity. There was also a non-exercising control group (C) of 9 subjects in this study. Fat-free mass was significantly increased in both the RT (+1.90 kg) and RT/W (+1.90 kg) groups as a result of the training program. No group showed significant changes in fat mass or relative body fat from pre- to post-training. Aerobic capacity was slightly, though significantly, increased in the RT/W group only. The RT group showed a significant increase (+44 kcal x day(-1)), while the RT/W group showed a significant decrease (-53 kcal x day(-1)) in resting metabolic rate post-training. RT can potentiate an increase in RMR through an increase in fat-free mass, and the decrease in RMR in the RT/W group may have been a result of heat acclimation from the walk training.     

Another step in the search for better oral rehydration solutions.

Objective: To compare resting metabolic rate (RMR) measured by indirect calorimetry versus RMR predicted by several published formulas in a sample of healthy young women.

Methods: RMR was measured using indirect calorimetry and predicted using 6 commonly used equations (Nelson, 1992; Mifflin, 1990; Owen, 1986; Schofield_Weight, 1985; Schofield_{Weight and Height}, 1985; Harris-Benedict, 1919) in 47 reportedly healthy young females (age = 22.8 ± 2.9 years; body mass index = 21.8 ± 2.1 kg/m²). Comparisons between measured versus predicted RMR were conducted using paired t tests, and agreement using Pearson's correlation coefficient, analysis of variance, and the method of Bland-Altman.

Results: All 6 equations overestimated measured RMR by 140–738 kcal/d (all p < 0.001). The proportion of subjects for whom measured versus predicted RMR differed by ±10% ranged from 74% (Nelson) to 100% (Harris-Benedict). The adjusted coefficients of determination (R²) between measured and predicted RMR ranged from 0.13 to 0.19 (all p < 0.05). Bland-Altman analysis R² values ranged from 0.03 (p = 0.233; Harris-Benedict) to 0.72 (p = 0.000; Owen). Given its continued popularity, we modified the Harris-Benedict equation (RMR_{modified Harris-Benedict} (kcal/d) = 738 / (RMR_{Harris-Benedict} ? 738)). Doing so reduced the mean difference between measured and predicted RMR from +738 kcal/d to ?0.53 kcal/d (p = 0.984).

Conclusion: No equation performed well, and none should be used interchangeably with measured RMR. We recommend that a new equation be validated for, and prospectively tested in, young women. In the interim, RMR should be measured in this population or predicted using the modified Harris-Benedict equation that we developed.     

Differences in resting metabolic rate between white and African-American young adults

OBJECTIVE: A reported lower resting metabolic rate (RMR) in African-American women than in white women could explain the higher prevalence of obesity in the former group. Little information is available on RMR in African-American men. RESEARCH METHODS AND PROCEDURES: We assessed RMR by indirect calorimetry and body composition by DXA in 395 adults ages 28 to 40 years (100 African-American men, 95 white men, 94 African-American women, and 106 white women), recruited from participants in the Coronary Artery Risk Development in Young Adults (CARDIA), Birmingham, Alabama, and Oakland, California, field centers. RESULTS: Using linear models, fat-free mass, fat mass, visceral fat, and age were significantly related to RMR, but the usual level of physical activity was not. After adjustment for these variables, mean RMR was significantly higher in whites (1665.07 +/- 10.78 kcal/d) than in African Americans (1585.05 +/- 11.02 kcal/d) by 80 +/- 16 kcal/d (p < 0.0001). The ethnic x gender interaction was not significant (p = 0.9512), indicating that the difference in RMR between African-American and white subjects was similar for men and women. DISCUSSION: RMR is approximately 5% higher in white than in African-American participants in CARDIA. The difference was the same for men and women and for lean and obese individuals. The prevalence of obesity is not higher in African-American men than in white men. Because of these reasons, we believe that RMR differences are unlikely to be a primary explanation for why African-American women are more prone to obesity than white women.     

Weight Training Increases Fat-Free Mass and Strength in Untrained Young Women

Objective To examine the effects of a weight training program on the resting metabolic rate, fat-free mass, strength, and dietary intake of untrained young women.Design A 12-week weight training program was completed by 20 previously untrained women aged 19 through 44 years.Subjects Twenty-three study subjects and 14 control subjects were recruited on a volunteer basis. Twenty study subjects and 10 control subjects completed the study.Interventions Study subjects participated in a 12-week moderate-intensity, progressive resistance weight training program consisting of 2 supervised sessions per week with 6 types of lifting exercises per session. Resting metabolic rate, fat-free mass, strength, and dietary intake were measured before and immediately after the study.Statistical analyses Repeated measures analysis of variance and t tests (unequal variance and paired) were used to determine interaction effects and differences within and between groups.Results The study group increased their fat-free mass (mean±standard deviation) from 44.2±5.4 kg to 46.2±6.0 kg (P<.001). Elbow flexion, elbow extension, and knee flexion strength all increased from 28.9±5.3 to 34.5±3.8, 16.9±4.9 to 22.1±5.3, and 39.5±8.6 to 48.6±7.3 ft-lb, respectively (P<.001). Percent body fat decreased from 29.8±2.8 to 27.2±2.6 (P<.001) without a significant change in body weight. Resting metabolic rate did not change significantly (P>.05).Application A moderate-intensity weight training program increased strength and fat-free mass and decreased body fat in normal-weight young women. Favorable changes in body composition were obtained without restricting food intake. The increase in fat-free mass did not increase resting metabolic rate significantly. J Am Diet Assoc. 1998;98:414-418.     

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.     

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.     

Accuracy of the Common Predictive Equations for Estimating Resting Energy Expenditure among Normal and Overweight Girl University Students

Objective: The aim of the present study was to determine the accuracy of commonly used predictive formulas of resting metabolic rate (RMR) compared to measured RMR in normal and overweight young females.

Methods: In this cross-sectional study, 98 female university students aged 18–30 years with body mass index 18 to 30 kg/m² were recruited. Anthropometric indices and body compositions were measured. RMR was measured by indirect calorimetry (FitMate, Cosmed, Rome, Italy) and estimated by 11 predictive formulas. The accuracy of the RMR formulas and mean percentage differences between estimated and measured values were calculated. Paired t test was used to compare estimated and measured RMRs.

Result: There were no significant differences between measured and estimated RMR by the 4 commonly used formulas (Mifflin, Cunningham, and World Health Organization [WHO]/Food and Agriculture Organization [FAO]). Among all of the equations, the Mifflin formula showed the lowest bias (?2.97 ± 116.43 kcal/day) at the group level and was the most accurate formula (80.23%) in normal and overweight participants. The over- and underestimated values were about 14% and 5.5%, respectively. In normal and overweight females, Mifflin was the most accurate formula, with 75.51% and 84.61% accuracy, respectively.

Conclusion: Given the current lack of a standardized formula that consistently delivers accurate results, the Mifflin formula can be recommended for estimating energy requirements in normal and overweight females in clinical practice.     

Diet and gene interaction.

Objective: To investigate the effect of chromium picolinate (CP) supplementation on body composition, resting metabolic rate (RMR), selected biochemical parameters and iron and zinc status in moderately obese women participating in a 12-week exercise program.

Methods: Forty-four women, 27 to 51 years of age, were randomly assigned to two groups based on their body mass index. Subjects received either 400 μg/day of chromium as a CP supplement or a placebo in double-blind fashion and participated in a supervised weight-training and walking program two days per week for 12 weeks. Body composition and RMR were measured at baseline, 6 and 12 weeks. Selected biochemical parameters and iron and zinc status were measured at baseline and 12 weeks.

Results: Body composition and RMR were not significantly changed by CP supplementation. No significant differences in fasting plasma glucose, serum insulin, plasma glucagon, serum C-peptide and serum lipid concentrations or in iron and zinc indices were found between the two groups over time. Serum total cholesterol concentration significantly decreased (p = 0.0016) over time for all subjects combined, probably as a result of the exercise training. Exercise training significantly reduced total iron binding capacity (TIBC) by 3% for all subjects combined (p = 0.0011).

Conclusions: Twelve weeks of 400 μg/day of chromium as a CP supplement did not significantly affect body composition, RMR, plasma glucose, serum insulin, plasma glucagon, serum C-peptide and serum lipid concentrations or iron and zinc indices in moderately obese women placed on an exercise program. The changes in serum total cholesterol levels and TIBC were a result of the exercise program.     

Energy costs of standard activities among Indian adults

OBJECTIVES: To estimate the energy cost of resting (RMR), sitting and standing for urban Indian adults and compare these estimates with the reported values. DESIGN: Energy costs were measured using oxylog while body fat was estimated using equipment (HBF300, OMRON Corporation, Japan) that works on the principle of bioelectrical impedance, for 24 men and 40 women, aged 20-50 y, engaged in sedentary activities. SETTINGS: Agharkar Research Institute, Pune, India. RESULTS: Mean energy cost (kJ/min) of resting (RMR), sitting and standing were significantly (P<0.01, for all) higher for men (4.01+/-0.42, 5.0+/-0.72 and 5.74+/-0.69, respectively) than women (3.54+/-0.28, 4.03+/-0.41 and 4.35+/-0.52, respectively). Gender difference increased with the level of activity, from 13% for RMR to 32% for standing. These differences reduced when adjusted (using analysis of covariance) for body weight and became non-significant on adjusting for fat-free mass (FFM) in the case of RMR and sitting activity. The measured values of energy cost (absolute and per kg weight) for these activities were similar to African subjects but lower compared to Asian or European subjects for both sexes. The stepwise regression analysis done separately by sexes showed weight (29%) in men and body mass index (44%) in women to be the best predictors of RMR, while regression analysis for combined sexes indicated FFM and height as predictors of RMR (r(2)=56%, P<0.01). If means to estimate body fat were not available, RMR could best be predicted with BMI and sex as predictors (r(2)=55%; P<0.01). This was mainly due to the fact that the sex differences in our population were more prominent in FFM than that in BMI. Our observations thus indicate the need to develop prediction equations separately for different populations owing to differences in their body compositions, especially in fat mass (FM) or FFM. CONCLUSION: The energy costs of activities were associated with body composition, especially with absolute fat-free mass, which may vary even with the same body fat percentage. Therefore, there is a need to develop separate prediction equations for different communities.     

An Increase in Fat-Free Mass is Associated with Higher Appetite and Energy Intake in Older Adults: A Randomised Control Trial

Cross-sectional studies in younger adults have demonstrated a positive association between energy intake (EI) and fat-free mass (FFM), with this relationship seemingly mediated by resting metabolic rate (RMR). Establishing a causal effect longitudinally would be prudent in older adults suffering from loss of appetite. We investigated the effects of FFM on RMR, appetite and EI in 39 healthy older adults (age: 66 ± 4 years, BMI: 25.1 ± 3.5 kg∙m²) assigned to either 12-week resistance training + protein supplementation group (RT + PRO) or control group (CON). Body composition, subjective appetite, leptin, insulin, RMR and laboratory-measured ad libitum EI were measured at baseline, weeks 6 and 12 of the intervention, while daily EI at baseline and week 12. FFM (+1.2 kg; p = 0.002), postprandial subjective appetite (+8 mm; p = 0.027), ad libitum EI (+119 kcal; p = 0.012) and daily EI (+133 kcal; p = 0.010) increased from baseline to week 12 in the RT + PRO. RMR, fasted subjective appetite, leptin and insulin concentrations remained unchanged (all p > 0.05). The increases ad libitum EI correlated with increases in FFM (r = 0.527, p = 0.001), with 54% of the change in EI attributed to FFM changes. In conclusion, FFM increases were associated with an increased ad libitum EI and postprandial appetite in older adults.     

Effects of exercise and food restriction on body composition and metabolic rate in obese women

Obese women (140-180% of ideal body weight) were studied on a metabolic ward during 1 wk of maintenance feeding, followed by 5 wk of 800 kcal/d (liquid formula diet). Five subjects participated in a supervised program of daily aerobic exercise and three subjects remained sedentary. Total weight loss was not different between exercising and nonexercising subjects but significantly more of the weight loss came from fat and less from fat-free mass in the exercising subjects. Resting metabolic rate (RMR) declined similarly in both groups (approximately 20%), even though exercising subjects were in greater negative energy balance due to the added energy cost of exercise. In summary, results from this controlled inpatient study indicate that exercise is beneficial when coupled with food restriction because it favors loss of body fat and preserves fat-free mass.     

Predictive Equation to Estimate Resting Metabolic Rate in Older Chilean Women

Resting metabolic rate (RMR) depends on body fat-free mass (FFM) and fat mass (FM), whereas abdominal fat distribution is an aspect that has yet to be adequately studied. The objective of the present study was to analyze the influence of waist circumference (WC) in predicting RMR and propose a specific estimation equation for older Chilean women. This is an analytical cross-sectional study with a sample of 45 women between the ages of 60 and 85 years. Weight, height, body mass index (BMI), and WC were evaluated. RMR was measured by indirect calorimetry (IC) and %FM using the Siri equation. Adequacy (90% to 110%), overestimation (>110%), and underestimation (<90%) of the FAO/WHO/UNU, Harris–Benedict, Mifflin-St Jeor, and Carrasco equations, as well as those of the proposed equation, were evaluated in relation to RMR as measured by IC. Normal distribution was determined according to the Shapiro–Wilk test. The relationship of body composition and WC with RMR IC was analyzed by multiple linear regression analysis. The RMR IC was 1083.6 ± 171.9 kcal/day, which was significantly and positively correlated with FFM, body weight, WC, and FM and inversely correlated with age (p < 0.001). Among the investigated equations, our proposed equation showed the best adequacy and lowest overestimation. The predictive formulae that consider WC improve RMR prediction, thus preventing overestimation in older women.     

The effects of either high-intensity resistance or endurance training on resting metabolic rate.

The effects of either 12-wk of high-intensity endurance or resistance training on resting metabolic rate (RMR) were investigated in 47 males aged 18-35 y. Subjects were randomly assigned to either a control (C), resistance-trained (RT) or endurance-trained (ET) group. After training both exercise groups showed significant declines in relative body fat either by reducing their total fat weight and maintaining fat-free weight (ET) or by reducing their total fat weight and increasing fat-free weight (RT). RMR did not significantly change after either training regimen although a small decline in energy intake was observed along with an increase in energy expenditure [ET, 2.721 MJ (650 kcal) per training day]. These results suggest that both endurance and resistance training may help to prevent an attenuation in RMR normally observed during extended periods of negative energy balance (energy intake less than expenditure) by either preserving or increasing a person's fat-free weight.     

Meta-analysis of resting metabolic rate in formerly obese subjects.

BACKGROUND: A low resting metabolic rate (RMR) for a given body size and composition is partly genetically determined and has been suggested to be a risk factor for weight gain. Moreover, a low relative RMR has been reported in some, but not all, studies of formerly obese persons. The inconsistent reports may be due to a lack of statistical power to detect small differences in RMR and improper adjustment for body size and composition. OBJECTIVE: We conducted a meta-analysis based on published studies of RMR in formerly obese persons [body mass index (in kg/m2) < or = 27] and matched control subjects who had never been obese. DESIGN: We performed both an individual subject data meta-analysis and a traditional meta-analysis. RESULTS: The individual subject data meta-analysis included 124 formerly obese and 121 control subjects. RMR adjusted for differences in fat-free mass and fat mass was 2.9% lower in formerly obese subjects than in control subjects (P = 0.09). A low relative RMR (> 1 SD below the mean of the control group) was found in 3.3% of the control subjects and in 15.3% of the formerly obese subjects [difference: 12% (95% CI: 4.7%, 19.3%); P < 0.003]. The traditional meta-analysis was based on 12 studies (including 94 formerly obese and 99 control subjects) and included 3 studies not represented in the individual subject data analysis. In this analysis, relative RMR was lower in the formerly obese group than in the control group by 5.1% (95% CI: 1.7%, 8.6%). CONCLUSIONS: Formerly obese subjects had a 3-5% lower mean relative RMR than control subjects; the difference could be explained by a low RMR being more frequent among the formerly obese subjects than among the control subjects. Whether the cause of the low RMR is genetic or acquired, the existence of a low RMR is likely to contribute to the high rate of weight regain in formerly obese persons.     

Postprandial resting metabolic rate and body composition in the moderately obese and normal-weight adult subjects at sitting posture

A reduced metabolic rate in the etiology of obesity has been a subject of controversy. The prediction of the energy requirements for the obese using reference values may therefore be distorted. In order to examine this possibility, resting metabolic rate (RMR) while the subject was sitting comfortably in a chair was measured in a total of 134 moderately obese and normal-weight subjects (68 women aged 20 to 71 with a mean of 53.1 and 66 men aged 20 to 63 with a mean of 36.5). RMR per kg of body weight was significantly lower in the female obese subjects, but not in the male obese subjects. There was no evidence of difference in RMR between obese and normal-weight subjects in either sex when RMR was indexed with fat-free mass (FFM), indicating no substantial decrease in the metabolism due to obesity. Multiple regression analyses indicate that standardization of RMR by FFM eliminates the apparent difference in RMR between the sexes, and the diminution of RMR with age was not observed. While the best and logical prediction of RMR is to use FFM, regression analyses suggest an alternative way of predicting RMR by an incorporation of subscapular skinfold thickness to adjust the different body composition in lean and obese subjects. Prediction equations of postprandial RMR (kcal/24-h) while sitting are RMR = 24.5 x FFM(kg) + 303.7, and RMR = 22.7 x weight(kg) - 13.6 x SSF (subscapular skinfold: mm) + 350.6. Problems in predicting RMR are discussed.     

Resting and total energy expenditure in patients with inflammatory bowel disease

Patients with inflammatory bowel disease often present with weight loss. Among possible causes, an elevated energy expenditure has frequently been suggested but is the least documented. In this study resting metabolic rate (RMR) and total daily energy expenditure (TDEE) were measured in 15 outpatients with inflammatory bowel diseases and in eight healthy control subjects. Measured RMR as a percentage of that predicted from fat-free mass was not significantly different for control subjects (102 +/- 9.8%, mean +/- SD) and patients (100 +/- 13.3%). TDEE, expressed as a multiple of RMR, was 1.70 +/- 0.31 for control subjects and 1.78 +/- 0.24 for patients. When patients were subgrouped as greater than or equal to 90% or less than 90% desirable body weight, a mean increase over RMR predicted from fat-free mass was seen in the underweight patients (106 +/- 9.3%) but not in normal-weight patients (99.0 +/- 15.6%). Mean TDEE/RMR values for the patient subgroups were 1.70 +/- 0.30 and 1.88 +/- 0.08, respectively. We conclude that stable outpatients with inflammatory bowel disease have only a minimal increase in energy needs.     

A Randomized Controlled Trial Evaluating Nutrition Counseling with or without Oral Supplementation in Malnourished HIV-Infected Patients

Objective To evaluate the effects of nutrition counseling with or without oral supplementation in malnourished patients infected with the human immunodeficiency virus (HIV).Design Randomized controlled trial.Subjects HIV-infected men (n=118) who were less than 90% of usual weight for height or who had lost more than 10% of body weight.Intervention Nutrition counseling alone (control group) vs nutrition counseling plus enteral supplementation (supplement group) for 6 weeks. All patients were instructed to consume a diet that exceeded estimated total energy expenditure by 960 kcal/day.Main outcome measures Weight, skinfold thickness, fat-free mass, grip strength, quality of life, and cognitive function (Buschke test).Statistical analyses Differences in baseline variables and outcomes were evaluated using analysis of variance or the Wilcoxon rank sum test.Results Ninety-nine men completed at least 4 weeks of treatment, 49 in the supplement group and 50 in the control group. Half the patients in each treatment group achieved at least 80% of their energy target. No differences in weight, skinfold thickness measurements, or quality of life were observed. Compared with the control group, the supplement group had larger increases in fat-free mass and grip strength, although the differences did not reach statistical significance.Applications In the short term, nutrition counseling with or without oral supplementation can achieve a substantial increase in energy intake in about 50% of malnourished HIV-infected patients. Although further study is needed to evaluate long-term effects, these findings suggest that nutrition counseling has an important role in the management of malnourished HIV-infected patients. J Am Diet Assoc. 1998;98:434-438.     

Changes in body weight, body composition and resting metabolic rate (RMR) in first-year university freshmen students

OBJECTIVES: The purpose of the present study was to document any changes that might occur in body weight, body composition, RMR, and dietary intake in newly enrolled college freshmen. METHODS: Body weight, RMR by ventilated O(2) consumption, body composition by bioelectrical impedance and dietary intakes were recorded in 27 first-year college freshmen during their initial 16-week semester. RESULTS: Mean body weight increased significantly with time (3.0 lbs; p < 0.001); 16 subjects (59%) gained >or= 3.0 lbs, while 6 subjects (22%) gained >or= 6 lbs. Percent fat mass significantly increased (p < 0.001), while lean body mass decreased (p < 0.001). Changes in RMR failed to reach statistical significance; however, there was a significant correlation between changes in weight and RMR (r = 0.45; p < 0.02). Mean reported calorie intake did not differ significantly between the beginning (1905 +/- 664 kcal) and end (1960 +/- 687 kcal) of the study. However, the differences ( approximately 55 kcal) are in the range necessary to support the mean 3 lb. weight gain. CONCLUSIONS: The present study supports the notion that freshmen students, on average, gain weight during their first semester; however, this weight gain may be more modest than generally perceived. The study also provides important new data on changes in diet, body composition and RMR.     

Resting metabolic rate and postprandial thermogenesis in highly trained and untrained males

The purpose was to compare the resting metabolic rate (RMR) and thermic effect of a meal (TEM) in exercise trained and untrained individuals. TEM was measured for 180 min and blood samples were drawn for determination of plasma insulin, glucose, triiodothyronine (T3) and thyroxine (T4). Results indicated that highly trained subjects demonstrated a higher RMR when expressed in kilocalories per minute and per kilogram fat-free weight (FFW) than do untrained subjects. TEM was lower in trained (55.8 +/- 3.1 kcal) than in untrained (79.2 +/- 3.7 kcal) subjects. No differences were noted between the two groups for plasma levels of insulin, glucose, T3, and T4. A higher RMR and lower TEM persisted in the trained group compared with the untrained group when groups were matched for FFW and body fat. Results support a higher RMR in endurance athletes and a lower TEM even after control is exerted over differences in body composition.