Resting metabolic rate in bodybuilding: Differences between indirect calorimetry and predictive equations.

BACKGROUND & AIMS: Estimating resting metabolic rate (RMR) is one of the main determinants of an athlete's energy needs. This study aimed to investigate the RMR of bodybuilding athletes using indirect calorimetry (IC) and compare it with predictive formulas proposed in the scientific literature. METHODS: 71 volunteers divided into four experimental groups: active control group for women (CGW; n = 16); active control group for men (CGM; n = 17); bodybuilder women (BBW; n = 13); and bodybuilder men (BBM; n = 25) were evaluated. The body composition was performed using the bioelectrical impedance (BIA), and the RMR was measured using an IC. The data obtained from the BIA instrument were used to calculate the RMR of all volunteers using six equations. Data normality was tested, and the unpaired t-test compared anthropometric parameters, body composition, and RMR. The Bland-Altman (B&A) plot was used to analyze the agreement between IC, BIA, and predictive equations, and the difference between the methods was calculated. An analysis of covariance (ANCOVA) with Bonferroni post hoc was used for RMR analysis and adjusted for body weight and skeletal muscle mass. RESULTS: The main findings indicated that the Johnstone equation showed a large discrepancy underestimating the RMR of BBW and BBM when compared to IC, and the De Lorenzo and Tinsley equations (a) approached the more accurate analysis method of measuring RMR in BBW and BBM, respectively. CONCLUSION: Professionals who work with bodybuilding and performance will be able to use the present study to improve their nutrition support.

Differential Responses of Liver and Hypothalamus to the Nutritional Condition During Lactation and Adult Life.

It was previously reported that liver glucose metabolism in rats under caloric restriction differs from that of freely-fed rats. This study hypothesized that these changes (1) were related to the expression of hypothalamic neuropeptides involved in metabolic control, and (2) were not a residual effect of litter size. To those purposes, liver glucose metabolism and hypothalamic expression of the orexigenic neuropeptides NPY (neuropeptide Y) and AgRP (agouti gene-related peptide); and of the anorexigenic neuropeptides POMC (pro-opiomelanocortin) and CART (cocaine- and amphetamine-related transcripts) were investigated. Male Wistar rats from two different litter sizes (G6 and G12, with 6 or 12 pups, respectively) were subjected to free feeding (GL, ad libitum), 50% caloric restriction (GR) or caloric restriction+ad libitum refeeding (GRL) until the age of 90 days. Biometric values were lower in GR than in GL, while in GRL they were totally or partially recovered. Blood glucose variation during the pyruvate tolerance test (PTT) was small in GR. During in situ liver perfusion, total, basal, and adrenaline-stimulated liver glucose outputs were high in GR, but additional glucose output in the presence of alanine was negligible. Refeeding (GRL) yielded values close to those of GL. Litter size did not consistently influence any of these variables. The expression of transcripts of the hypothalamic neuropeptides was responsive to feeding regimen, litter size and/or their interaction and differed from G6 to G12, while the metabolic changes of the liver were qualitatively equal in both GR. Therefore, the changes in glucose metabolism in the liver of rats under caloric restriction were not determined by either litter size or hypothalamic neuropeptide expression and were linked only to the prevailing feeding regimen of the adult animal.

Sports and Functional Training Improve a Subset of Obesity-Related Health Parameters in Adolescents: A Randomized Controlled Trial.

To investigate the effects of two different modes of physical activity on body composition, physical fitness, cardiometabolic risk, and psychological responses in female adolescents participating in a multi-disciplinary program. The 12-week randomized intervention included 25-adolescents with overweight divided into two groups: sports practice-SPG and functional training-FTG. The SPG intervention was divided into three sports: basketball, handball, and futsal. SPG participants performed one sport 3-times/week, over the course of 1 month. The FTG performed concurrent exercises 3-times/week. This study was registered in Clinical Trials Registry Platform under number: RBR-45ywtg and registered in Local Ethics Committee number: 2,505.200/2018. The intensity of physical exercises-PE was matched between groups by the rating of perceived exertion. The primary outcome was body composition, and secondary outcomes were physical fitness, cardiometabolic risk, and psychological responses. There was a significant time-effect for body mass, body mass index, and low-density lipoprotein (LDL-c), all being reduced. There were increases over time for musculoskeletal mass, aerobic fitness, and high-density lipoprotein (HDL-c) (p < 0.05). There was a group time interaction with body fat percentage being lower post-intervention in the SPG (p < 0.05). No significant differences were observed for the other variables. Both physical activity models were effective in improving a subset of obesity-related health parameters. The findings should be extended by further investigation using more sophisticated measures of energy expenditure. Clinical Trial Registration: https://ensaiosclinicos.gov.br/, identifier: RBR-45ywtg.

Modulation of liver glucose output by free or restricted feeding in the adult rat is independent of litter size.

BACKGROUND: Caloric restriction since birth changes glucose metabolism by the liver in overnight-fasted rats to a fed-like pattern, in which glucose output is large but gluconeogenesis is negligible. It was investigated whether these changes could be a residual effect of the nutritional condition during lactation and what could be the mechanism of such change. METHODS: Newborn Wistar rat pups were arranged in litters of 6 or 12 (G6 and G12). After weaning, the male pups were divided in: G6L and G12 L, fed freely until the age of 90 days (freely-fed groups); G6R and G12R, given 50% of the GL ingestion (food-restricted groups) until 90 days of age; G6RL and G12RL, given 50% of the GL ingestion until 60 days of age and fed freely until 90 days of age (refed groups). The experimental protocols were carried out at the age of 90 days after overnight fasting. Pairs of groups were compared through t test; other statistical comparisons were made with one-way ANOVA with Tukey post hoc text. RESULTS: Caloric restriction was effective in decreasing body and fat weights, total cholesterol and LDL. These effects were totally or partially reversed after 30 days of refeeding (groups GRL). During liver perfusion, the high glucose output of the GRs was further enhanced by adrenaline (1 µM), but not by lactate infusion. In contrast, in groups G6L, G12 L, G6RL and G12RL glycogenolysis (basal and adrenaline-stimulated glucose output) was low and gluconeogenesis from lactate was significant. A twofold increase in liver content of PKA in group G6R suggests that liver sensitivity to glucagon and adrenaline was higher because of caloric restriction, resulting in enhanced glucose output. CONCLUSIONS: As glucose output was not affected by litter size, liver glucose metabolism in the adult rat, in contrast to other metabolic processes, is not a programmed effect of the nutritional condition during lactation. In addition, the increased expression of PKA points to a higher sensitivity of the animals under caloric restriction to glycogenolytic hormones, a relevant condition for glucose homeostasis during fasting.