scholarly journals Cardiorespiratory Fitness May Influence Metabolic Inflexibility During Exercise in Obese Persons

2019 ◽  
Vol 104 (12) ◽  
pp. 5780-5790 ◽  
Author(s):  
Francisco J Amaro-Gahete ◽  
Guillermo Sanchez-Delgado ◽  
Ignacio Ara ◽  
Jonatan R. Ruiz
Keyword(s):  
Cardiorespiratory Fitness ◽  
Lean Mass ◽  
Normal Weight ◽  
Whole Body ◽  
Graded Exercise ◽  
Obese Subjects ◽  
Maximal Fat Oxidation ◽  
Metabolic Inflexibility ◽  
Overweight Subjects ◽  
Body Lean Mass

Abstract Context We examined whether obese individuals have a reduced maximal fat oxidation (MFO) and the intensity that elicit MFO (Fatmax) compared with normal weight and overweight persons, taking into account their level of cardiorespiratory fitness. Methods The study subjects were 138 sedentary adults (87 women) aged 30.1 ± 13.6 years. Based on their body mass index, subjects were categorized as being of normal weight (n = 66), overweight (n = 48), or obese (n = 24). MFO and Fatmax were determined for all subjects by indirect calorimetry, using a walking graded exercise test. MFO was expressed in absolute terms (g/min) and relative to whole-body lean mass (mg/kgleanmass/min). Cardiorespiratory fitness was assessed via a maximal treadmill test. Results No differences in absolute MFO and Fatmax values were seen between the obese, normal weight, and overweight subjects (all P > 0.2), although after adjusting for cardiorespiratory fitness, the obese subjects returned significantly higher values than did their normal weight and overweight counterparts (all P < 0.03). However, when expressed with respect to lean mass, the MFO of the normal weight subjects was significantly greater than that of the overweight and obese subjects, independent of age, sex, or cardiorespiratory fitness. Conclusions Obese individuals have higher absolute MFO values when cardiorespiratory fitness is taken into account, but when expressed with respect to lean mass, normal weight individuals show a greater capacity to oxidize fat during exercise per unit of metabolically active tissue independent of age, sex, or cardiorespiratory fitness. These findings suggest that obese individuals may suffer from metabolic inflexibility during exercise.

scholarly journals Protein Intake Greater than the RDA Differentially Influences Whole-Body Lean Mass Responses to Purposeful Catabolic and Anabolic Stressors: A Systematic Review and Meta-analysis

2019 ◽  
Vol 11 (3) ◽  
pp. 548-558 ◽  
Author(s):  
Joshua L Hudson ◽  
Yu Wang ◽  
Robert E Bergia III ◽  
Wayne W Campbell
Keyword(s):  
Systematic Review ◽  
Lean Mass ◽  
Weighted Mean Difference ◽  
Meta Analysis ◽  
Energy Restriction ◽  
Whole Body ◽  
Weighted Mean ◽  
Randomized Controlled ◽  
Body Lean Mass ◽  
Apparently Healthy

ABSTRACT Under stressful conditions such as energy restriction (ER) and physical activity, the RDA for protein of 0.8 g · kg−1 · d−1 may no longer be an appropriate recommendation. Under catabolic or anabolic conditions, higher protein intakes are proposed to attenuate the loss or increase the gain of whole-body lean mass, respectively. No known published meta-analysis compares protein intakes greater than the RDA with intakes at the RDA. Therefore, we conducted a systematic review and meta-analysis to assess the effects of protein intakes greater than the RDA, compared with at the RDA, on changes in whole-body lean mass. Three researchers independently screened 1520 articles published through August 2018 using the PubMed, Scopus, CINAHL, and Cochrane databases, with additional articles identified in published systematic review articles. Randomized, controlled, parallel studies ≥6 wk long with apparently healthy adults (≥19 y) were eligible for inclusion. Data from 18 studies resulting in 22 comparisons of lean mass changes were included in the final overall analysis. Among all comparisons, protein intakes greater than the RDA benefitted changes in lean mass relative to consuming the RDA [weighted mean difference (95% CI): 0.32 (0.01, 0.64) kg, n = 22 comparisons]. In the subgroup analyses, protein intakes greater than the RDA attenuated lean mass loss after ER [0.36 (0.06, 0.67) kg, n = 14], increased lean mass after resistance training (RT) [0.77 (0.23, 1.31) kg, n = 3], but did not differentially affect changes in lean mass [0.08 (−0.59, 0.75) kg, n = 7] under nonstressed conditions (no ER + no RT). Protein intakes greater than the RDA beneficially influenced changes in lean mass when adults were purposefully stressed by the catabolic stressor of dietary ER with and without the anabolic stressor of RT. The RDA for protein is adequate to support lean mass in adults during nonstressed states. This review was registered at www.crd.york.ac.uk/prospero as CRD 42018106532.

Three weeks of caloric restriction alters protein metabolism in normal-weight, young men

2005 ◽  
Vol 289 (3) ◽  
pp. E446-E455 ◽  
Author(s):  
Anne L. Friedlander ◽  
Barry Braun ◽  
Margaret Pollack ◽  
Jay R. MacDonald ◽  
Charles S. Fulco ◽  
...  
Keyword(s):  
Caloric Restriction ◽  
Lean Mass ◽  
Nitrogen Balance ◽  
Exercise Performance ◽  
Young Men ◽  
Normal Weight ◽  
Peak Oxygen Consumption ◽  
Whole Body ◽  
Aerobic Performance ◽  
Pool Model

The effects of prolonged caloric restriction (CR) on protein kinetics in lean subjects has not been investigated previously. The purpose of this study was to test the hypotheses that 21 days of CR in lean subjects would 1) result in significant losses of lean mass despite a suppression in leucine turnover and oxidation and 2) negatively impact exercise performance. Nine young, normal-weight men [23 ± 5 y, 78.6 ± 5.7 kg, peak oxygen consumption (V̇o2 peak) 45.2 ± 7.3 ml·kg−1·min−1, mean ± SD] were underfed by 40% of the calories required to maintain body weight for 21 days and lost 3.8 ± 0.3 kg body wt and 2.0 ± 0.4 kg lean mass. Protein intake was kept at 1.2 g·kg−1·day−1. Leucine kinetics were measured using α-ketoisocaproic acid reciprocal pool model in the postabsorptive state during rest and 50 min of exercise (EX) at 50% of V̇o2 peak. Body composition, basal metabolic rate (BMR), and exercise performance were measured throughout the intervention. At rest, leucine flux (≈131 μmol·kg−1·h−1) and oxidation (Rox; ≈19 μmol·kg−1·h−1) did not differ pre- and post-CR. During EX, leucine flux (129 ± 6 vs. 121 ± 6) and Rox (54 ± 6 vs. 46 ± 8) were lower after CR than they were pre-CR. Nitrogen balance was negative throughout the intervention (≈3.0g N/day), and BMR declined from 1,898 ± 262 to 1,670 ± 203 kcal/day. Aerobic performance (V̇o2 peak, endurance cycling) was not impacted by CR, but arm flexion endurance decreased by 20%. In conclusion, 3 wk of caloric restriction reduced leucine flux and Rox during exercise in normal-weight young men. However, despite negative nitrogen balance and loss of lean mass, whole body exercise performance was well maintained in response to CR.

scholarly journals Association of 3p27.1 Variants with Whole Body Lean Mass Identified by a Genome-wide Association Study

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Shu Ran ◽  
Yu-Xue Zhang ◽  
Lu Liu ◽  
Zi-Xuan Jiang ◽  
Xiao He ◽  
...  
Keyword(s):  
Association Study ◽  
Lean Mass ◽  
Genome Wide Association Study ◽  
Genome Wide Association ◽  
Whole Body ◽  
Genome Wide ◽  
A Genome ◽  
Body Lean Mass

Effects of prolonged fasting on AMPK signaling, gene expression, and mitochondrial respiratory chain content in skeletal muscle from lean and obese individuals

2013 ◽  
Vol 304 (9) ◽  
pp. E1012-E1021 ◽  
Author(s):  
Marjolein A. Wijngaarden ◽  
Gerard C. van der Zon ◽  
Ko Willems van Dijk ◽  
Hanno Pijl ◽  
Bruno Guigas
Keyword(s):  
Gene Expression ◽  
Skeletal Muscle ◽  
Respiratory Chain ◽  
Mitochondrial Respiratory Chain ◽  
Whole Body ◽  
Prolonged Fasting ◽  
Metabolic Gene Expression ◽  
Obese Subjects ◽  
Metabolic Inflexibility ◽  
Mitochondrial Respiratory

Obesity in humans is often associated with metabolic inflexibility, but the underlying molecular mechanisms remain incompletely understood. The aim of the present study was to investigate how adaptation to prolonged fasting affects energy/nutrient-sensing pathways and metabolic gene expression in skeletal muscle from lean and obese individuals. Twelve lean and 14 nondiabetic obese subjects were fasted for 48 h. Whole body glucose/lipid oxidation rates were determined by indirect calorimetry, and blood and skeletal muscle biopsies were collected and analyzed. In response to fasting, body weight loss was similar in both groups, but the decrease in plasma insulin and leptin and the concomitant increase in growth hormone were significantly attenuated in obese subjects. The fasting-induced shift from glucose toward lipid oxidation was also severely blunted. At the molecular level, the expression of insulin receptor-β (IRβ) was lower in skeletal muscle from obese subjects at baseline, whereas the fasting-induced reductions in insulin signaling were similar in both groups. The protein expression of mitochondrial respiratory chain components, although not modified by fasting, was significantly reduced in obese subjects. Some minor differences in metabolic gene expression were observed at baseline and in response to fasting. Surprisingly, fasting reduced AMPK activity in lean but not in obese subjects, whereas the expression of AMPK subunits was not affected. We conclude that whole body metabolic inflexibility in response to prolonged fasting in obese humans is associated with lower skeletal muscle IRβ and mitochondrial respiratory chain content as well as a blunted decline of AMPK activity.

Maximal fat oxidation rate is higher in fit women and unfit women with obesity, compared to normal weight unfit women

2021 ◽  
Author(s):  
Jacob Frandsen ◽  
Ida Marie Dahlgaard Hansen ◽  
Julie Fensmark Wismann ◽  
Maria Høyer Olsen ◽  
Morten Runge Brage-Andersen ◽  
...  
Keyword(s):  
Young Women ◽  
Exercise Test ◽  
Oxidation Rate ◽  
Fat Oxidation ◽  
Cycle Ergometer ◽  
Normal Weight ◽  
Middle Aged ◽  
Graded Exercise ◽  
Maximal Fat Oxidation ◽  
Related Increase

Abstract Introduction Maximal fat oxidation rate (MFO) is higher in aerobically fit vs. unfit young men, but this training related increase in MFO is attenuated in middle-aged men. Further, it has also been found that unfit men with obesity may have an elevated MFO compared to unfit normal-weight men. Aim/Hypothesis Based hereupon, we aimed to investigate whether a fitness related higher MFO were attenuated in middle-aged women compared to young women. Also, we aimed to investigate if unfit women with obesity have a higher MFO compared to unfit normal-weight women. We hypothezised that the training related elevated MFO was attenuated in middle-aged women, but that unfit women with obesity would have an elevated MFO compared to unfit normal-weight women. Methods We recruited a total of 70 women stratified into six groups: Young fit (n=12), young unfit (n=12) middle-aged fit (n=12), middle-aged unfit (n=12), unfit young women with obesity (n=12) and unfit middle-aged women with obesity (n=10). Body composition and resting blood samples were obtained and MFO was measured by a graded exercise test on a cycle ergometer via indirect calorimetry. Subsequently, a maximal exercise test was performed to establish V̇O2peak. Results Young and middle-aged fit women had a higher MFO compared to age-matched unfit women, and young fit women had a higher MFO compared to fit middle-aged women. Unfit women with obesity, independent of age, had a higher MFO compared to their normal-weight and unfit counterparts. Conclusion The training related increase in MFO seems maintained in middle-aged women and secondly, we find that unfit women with obesity, independent of age have a higher MFO compared to unfit normal-weight women.

scholarly journals Assessment of body composition in normal weighing and obese subjects by the bioelectrical impedance method

1995 ◽  
Vol 41 (4) ◽  
pp. 19-21
Author(s):  
L. I. Bershtein ◽  
Ye. V. Tsyrlina ◽  
Ye. B. Samoilova ◽  
I. G. Kovalenko
Keyword(s):  
Body Composition ◽  
Urinary Excretion ◽  
Personal Computer ◽  
Lean Mass ◽  
Subcutaneous Fat ◽  
Bioelectrical Impedance ◽  
Whole Body ◽  
Impedance Method ◽  
Endocrine Diseases ◽  
Obese Subjects

Body composition (lean mass, fat content) was assessed in 32 women aged 21 to 78 by measuring the thickness of subcutaneous fat in 4 typical sites and urinary excretion of creatinine, and estimating whole-body bioelectrical impedance (BI) by tetrapolar analyzer attached to personal computer. Results of BI measurements better correlated with body composition values assessed from the thickness of subcutaneous fat (particularly so in subjects aged under 50 and with Broca’s index from 0 to +19%). Hence, BI assessment may be used to evaluate body composition in patients with various endocrine diseases before the treatment and to monitor its efficacy in some diseases.

scholarly journals Circulatory microRNAs are not effective biomarkers of muscle size and function in middle-aged men

2019 ◽  
Vol 316 (2) ◽  
pp. C293-C298 ◽  
Author(s):  
Randall F. D’Souza ◽  
Nina Zeng ◽  
Sally D. Poppitt ◽  
David Cameron-Smith ◽  
Cameron J. Mitchell
Keyword(s):  
Lean Mass ◽  
Knee Extension ◽  
Muscle Size ◽  
Whole Body ◽  
Regulatory Function ◽  
Middle Aged ◽  
Cross Sectional ◽  
Total Body ◽  
And Function ◽  
Body Lean Mass

Loss of muscle size and strength with aging is a major cause of morbidity. Although muscle size and strength are measured by imaging or fiber cross-sectional staining and exercise testing, respectively, the development of circulatory biomarkers for these phenotypes would greatly simplify identification of muscle function deficits. MicroRNAs (miRNAs) are short noncoding RNAs that regulate gene translation and, thereby, contribute to muscle phenotype. To assess circulatory miRNAs (c-miRNAs) applicability as potential biomarkers of muscular phenotypes, fasting plasma and muscle samples were obtained from 50 middle-aged healthy men [mean  (SD); age: 48.8 yr (SD 4.5); BMI: 26.6 kg/m2 (SD 3.3)]. RT-PCR of 38 miRNAs with known regulatory function within skeletal muscle identified four c-miRNAs (miR-221, miR-451a, miR-361, and miR-146a) related to either total body lean mass, leg lean mass, and 50% thigh cross-sectional area (CSA), but not strength. There was no relationship with the expression of these miRNAs in muscle. Six miRNAs within muscle were correlated with whole body lean mass, leg lean mass, and isometric knee extension torque (miR-133a and miR-146a), and 50% thigh CSA (miR-486, miR-208b, miR-133b, and miR-208a). Only miR-23b demonstrated a relationship between tissue and circulatory expression; however, only 10% of the variance was explained. miR-146a in both plasma and muscle was related to phenotype; however, no relationship between plasma and muscle expression was evident. A different subset of miRNAs correlated to muscle phenotype in muscle compared with plasma samples, suggesting that c-miRNA biomarkers of muscle phenotype are likely unrelated to muscle expression in healthy individuals.

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