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Effects of a low carbohydrate weight loss diet on exercise capacity and tolerance in obese subjects.

URL: https://onlinelibrary.wiley.com/doi/full/10.1038/oby.2009.134

Journal: Obesity

Publication Date: 09/2012

Summary: Dietary restriction and increased physical activity are recommended for obesity treatment. Very low carbohydrate diets are used to promote weight loss, but their effects on physical function and exercise tolerance in overweight and obese individuals are largely unknown. The aim of this study was to compare the effects of a very low carbohydrate, high fat (LC) diet with a conventional high carbohydrate, low fat (HC) diet on aerobic capacity, fuel utilization during submaximal exercise, perceived exercise effort (RPE) and muscle strength. Sixty subjects (age: 49.2 ± 1.2 years; BMI: 33.6 ± 0.5 kg/m2) were randomly assigned to an energy restricted (∼6–7 MJ, 30% deficit), planned isocaloric LC or HC for 8 weeks. At baseline and week 8, subjects performed incremental treadmill exercise to exhaustion and handgrip and isometric knee extensor strength were assessed. Weight loss was greater in LC compared with HC (8.4 ± 0.4% and 6.7 ± 0.5%, respectively; P = 0.01 time × diet). Peak oxygen uptake and heart rate were unchanged in both groups (P > 0.17). Fat oxidation increased during submaximal exercise in LC but not HC (P < 0.001 time × diet effect). On both diets, perception of effort during submaximal exercise and handgrip strength decreased (P ≤ 0.03 for time), but knee extensor strength remained unchanged (P > 0.25). An LC weight loss diet shifted fuel utilization toward greater fat oxidation during exercise, but had no detrimental effect on maximal or submaximal markers of aerobic exercise performance or muscle strength compared with an HC diet. Further studies are required to determine the interaction of LC diets with regular exercise training and the long‐term health effects.

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A carbohydrate-restricted diet during resistance training promotes more favorable changes in body composition and markers of health in obese women with and without insulin resistance

URL: https://www.ncbi.nlm.nih.gov/pubmed/21673483

Journal: The Physician and Sports Medicine

Publication Date: 05/2011

Summary: To determine whether sedentary obese women with elevated levels of homeostatic model assessment (HOMA) insulin resistance (ie, > 3.5) experience greater benefits from an exercise + higher-carbohydrate (HC) or carbohydrate-restricted weight loss program than women with lower HOMA levels. 221 women (age, 46.5 ± 12 years; body weight, 90.3 ± 16 kg; body mass index, 33.8 ± 5 kg/m(2)) participated in a 10-week supervised exercise and weight loss program. The fitness program involved 30 minutes of circuit-style resistance training 3 days per week. Subjects were prescribed low-fat (30%) isoenergetic diets that consisted of 1200 kcals per day for 1 week (phase 1) and 1600 kcals per day for 9 weeks (phase 2) with HC or higher protein (HP). Fasting blood samples, body composition, anthropometry, resting energy expenditure, and fitness measurements were obtained at 0 and 10 weeks. Subjects were retrospectively stratified into lower (LH) or higher (HH) than 3.5 HOMA groups. Data were analyzed by multivariate analysis of variance with repeated measures and are presented as mean ± standard deviation changes from baseline. Baseline HOMA levels in the LH group were significantly lower than those in the HH group (LH, 0.6 ± 0.7; HH, 6.3 ± 3.4; P = 0.001). Diet and training significantly decreased body weight (-3.5 ± 3 kg), fat mass (-2.7 ± 3 kg), blood glucose (-3%), total cholesterol (-4.5%), low-density lipoproteins (-5%), triglycerides (-5.9%), systolic blood pressure (-2.6%), and waist circumference (-3.7%), while increasing peak aerobic capacity (7.3%). Subjects in the HP group experienced greater weight loss (-4.4 ± 3.6 kg vs -2.6 ± 2.9 kg), fat loss (-3.4 ± 2.7 kg vs -1.7 ± 2.0 kg), reductions in serum glucose (3% vs 2%), and decreases in serum leptin levels (-30.8% vs -10.8%) than those in the HC group. Participants in the HH (-14.1%) and HP-HH (-21.6%) groups observed the greatest reduction in serum blood glucose. A carbohydrate-restricted diet promoted more favorable changes in weight loss, fat loss, and markers of health in obese women who initiated an exercise program compared with a diet higher in carbohydrate. Additionally, obese women who initiated training and dieting with higher HOMA levels experienced greater reductions in blood glucose following an HP diet.

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Effects of an omnivorous diet compared with a lactoovovegetarian diet on resistance-training-induced changes in body composition and skeletal muscle in older men

URL: https://academic.oup.com/ajcn/article/70/6/1032/4729141

The American Journal of Clinical Nutrition

Publication Date: 12/1999

Summary: Very limited data suggest that meat consumption by older people may promote skeletal muscle hypertrophy in response to resistance training (RT). The objective of this study was to assess whether the consumption of an omnivorous (meat-containing) diet would influence RT-induced changes in whole-body composition and skeletal muscle size in older men compared with a lactoovovegetarian (LOV) (meat-free) diet. Nineteen men aged 51–69 y participated in the study. During a 12-wk period of RT, 9 men consumed their habitual omnivorous diets, which provided ≈50% of total dietary protein from meat sources (beef, poultry, pork, and fish) (mixed-diet group). Another 10 men were counseled to self-select an LOV diet (LOV-diet group). Maximal strength of the upper- and lower-body muscle groups that were exercised during RT increased by 10–38% (P < 0.001), independent of diet. The RT-induced changes in whole-body composition and skeletal muscle size differed significantly between the mixed- and LOV-diet groups (time-by-group interactions, P < 0.05). With RT, whole-body density, fat-free mass, and whole-body muscle mass increased in the mixed diet group but decreased in the LOV- diet group. Type II muscle fiber area of the vastus lateralis muscle increased with RT for all men combined (P < 0.01), and the increase tended to be greater in the mixed-diet group (16.2 ± 4.4 %) than in the LOV diet group (7.3 ± 5.1%). Type I fiber area was unchanged with RT in both diet groups. Consumption of a meat-containing diet contributed to greater gains in fat-free mass and skeletal muscle mass with RT in older men than did an LOV diet.

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Effects of a 12-Week Very-Low Carbohydrate High-Fat Diet on Maximal Aerobic Capacity, High-Intensity Intermittent Exercise, and Cardiac Autonomic Regulation: Non-randomized Parallel-Group Study

URL: https://www.frontiersin.org/articles/10.3389/fphys.2019.00912/full

Journal: Frontiers in Physiology

 Publication Date: 07/2019

 Summary: The 12 week VLCHF diet did not impair high-intensity continuous or intermittent exercise lasting up to 25 min, nor did it impair maximal cardiorespiratory performance or autonomic nervous system (ANS) activity.

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Effects of a 12-Week Very-Low Carbohydrate High-Fat Diet on Maximal Aerobic Capacity, High-Intensity Intermittent Exercise, and Cardiac Autonomic Regulation: Non-randomized Parallel-Group Study

URL: https://www.frontiersin.org/articles/10.3389/fphys.2019.00912/full#F4

Journal: Fronteirs in Physiology

 Publication Date: 07/2019

 Summary: Study of 24 healthy males on a 12 week VLCHF diet vs standard diet. The 12 week VLCHF diet did not impair high-intensity continuous or intermittent exercise lasting up to 25 min, nor did it impair maximal cardiorespiratory performance or autonomic nervous system (ANS) activit

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A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males

URL: https://www.hindawi.com/journals/jnme/2016/9104792/

Journal: Journal of Nutrition and Metabolism

 Publication Date: 09/2016

Summary: In male subjects with several years of experience with resistance training, chronic consumption of a diet high in protein had no harmful effects on any measures of health. Furthermore, there was no change in body weight, fat mass, or lean body mass despite eating more total calories and protein.

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Higher Protein Intake Is Associated with Higher Lean Mass and Quadriceps Muscle Strength in Adult Men and Women

URL: https://academic.oup.com/jn/article/145/7/1569/4616773

Journal: The Journal of Nutrition

Publication Date: 07/2015

 Summary: Our findings suggest that maintaining adequate protein intake with age may help preserve muscle mass and strength in adult men and women. Dietary protein types may differentially affect muscle mass and strength. Whether PP is a marker of dietary quality or has a direct effect on muscle strength (independent of lean mass) needs to be further clarified.

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Muscle Mass Index as a Predictor of Longevity in Older-Adults

URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4035379/

Journal: American Journal of Medicine

Publication Date: 06/2014

Summary: This study demonstrates the survival predication ability of relative muscle mass and highlights the need to look beyond total body mass in assessing the health of older adults.

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Protein-enriched diet, with the use of lean red meat, combined with progressive resistance training enhances lean tissue mass and muscle strength and reduces circulating IL-6 concentrations in elderly women: a cluster randomized controlled trial

URL: https://academic.oup.com/ajcn/article/99/4/899/4637870

Journal: The American Journal of Clinical Nutrition

Publication Date: 04/2014

Summary: 100 elderly women were randomized to a high protein diet supplemented with lean red meat combined with progressive resistance training versus progressive resistance training with a control diet. Lean tissue mass and strenghth increased more in the meat supplemented group. IGF-1 increase more and IL-6 decreased more in the meat supplemented group

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Midlife muscle strength and human longevity up to age 100 years: a 44-year prospective study among a decedent cohort

URL: https://link.springer.com/article/10.1007/s11357-011-9256-y

Journal: Age

 Publication Date: 06/2012

 Summary: We studied prospectively the midlife handgrip strength, living habits, and parents’ longevity as predictors of length of life up to becoming a centenarian. The participants were 2,239 men from the Honolulu Heart Program/Honolulu–Asia Aging Study who were born before the end of June 1909 and who took part in baseline physical assessment in 1965–1968, when they were 56–68 years old.High midlife grip strength and long-lived mother may indicate resilience to aging, which, combined with healthy lifestyle, increases the probability of extreme longevity.