Exercise has a profound effect on muscle growth, which can occur only if muscle protein synthesis exceeds muscle protein breakdown; there must be a positive muscle protein balance. Resistance exercise improves muscle protein balance, but, in the absence of food intake, the balance remains negative (i.e., catabolic). The response of muscle protein metabolism to a resistance exercise bout lasts for 24-48 hours; thus, the interaction between protein metabolism and any meals consumed in this period will determine the impact of the diet on muscle hypertrophy. Amino acid availability is an important regulator of muscle protein metabolism. The interaction of postexercise metabolic processes and increased amino acid availability maximizes the stimulation of muscle protein synthesis and results in even greater muscle anabolism than when dietary amino acids are not present. Hormones, especially insulin and testosterone, have important roles as regulators of muscle protein synthesis and muscle hypertrophy. Following exercise, insulin has only a permissive role on muscle protein synthesis, but it appears to inhibit the increase in muscle protein breakdown. Ingestion of only small amounts of amino acids, combined with carbohydrates, can transiently increase muscle protein anabolism, but it has yet to be determined if these transient responses translate into an appreciable increase in muscle mass over a prolonged training period.
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Exercise, Protein Metabolism, and Muscle Growth
Kevin D. Tipton and Robert R. Wolfe
Effect of Exercising in the Heat on Intestinal Fatty Acid-Binding Protein, Endotoxins, and Lipopolysaccharide-Binding Protein Markers in Trained Athletic Populations: A Systematic Literature Review
Alice Wallett, Julien D. Périard, Philo Saunders, and Andrew McKune
The gastrointestinal epithelium plays an important role in host health, contributing to the body’s ability to absorb nutrients and regulate immune homeostasis. Comprised of epithelial cell membranes and bound by tight junction proteins, it creates a dynamic and semipermeable wall between intestinal
The Effects of a High-Protein Diet on Markers of Muscle Damage Following Exercise in Active Older Adults: A Randomized, Controlled Trial
Tom Clifford, Eleanor J. Hayes, Jadine H. Scragg, Guy Taylor, Kieran Smith, Kelly A. Bowden Davies, and Emma J. Stevenson
( Brisswalter & Nosaka, 2013 ; Doering, Jenkins, et al., 2016 ; Easthope et al., 2010 ). The reasons for this are likely multifactorial, but one recent study suggested that the so-called anabolic resistance associated with old age, characterized by an impaired muscle protein synthetic response, is likely to
Effects of Exercise on Dietary Protein Requirements
Peter W.R. Lemon
This paper reviews the factors (exercise intensity, carbohydrate availability, exercise type, energy balance, gender, exercise training, age, and timing of nutrient intake or subsequent exercise sessions) thought to influence protein need. Although there remains some debate, recent evidence suggests that dietary protein need increases with rigorous physical exercise. Those involved in strength training might need to consume as much as 1.6 to 1.7 g protein ⋅ kg−1 day−1 (approximately twice the current RDA) while those undergoing endurance training might need about 1.2 to 1.4 g ⋅ kg−1 day−1 (approximately 1.5 times the current RDA). Future longitudinal studies are needed to confirm these recommendations and assess whether these protein intakes can enhance exercise performance. Despite the frequently expressed concern about adverse effects of high protein intake, there is no evidence that protein intakes in the range suggested will have adverse effects in healthy individuals.
Intake of Animal Protein Blend Plus Carbohydrate Improves Body Composition With no Impact on Performance in Endurance Athletes
Fernando Naclerio, Eneko Larumbe-Zabala, Mar Larrosa, Aitor Centeno, Jonathan Esteve-Lanao, and Diego Moreno-Pérez
The current daily protein recommendation for regular endurance exercisers is between 1.2 and 1.6 ( Thomas et al., 2016 ) or up to 1.8 g·kg −1 ·body mass for trained endurance athletes ( Jager et al., 2017 ). Accordingly, Kato et al. ( 2016 ), using the amino acid oxidation method, suggested an
Moderate Exercise, Postprandial Energy Expenditure, and Substrate Use in Varying Meals in Lean and Obese Men
Petra Stiegler, S. Andrew Sparks, and Adam Cunliffe
Maximizing postprandial energy expenditure and fat oxidation could be of clinical relevance for the treatment of obesity. This study investigated the effect of prior exercise on energy expenditure and substrate utilization after meals containing varying amounts of macronutrients. Eight lean (11.6% ± 4.0% body fat, M ± SD) and 12 obese (35.9% ± 5.3% body fat) men were randomly assigned to a protein (43% protein, 30% carbohydrate) or a carbohydrate (10% protein, 63% carbohydrate) meal. The metabolic responses to the meals were investigated during 2 trials, when meals were ingested after a resting period (D) or cycling exercise (Ex+D; 65% of oxygen consumption reserve, 200 kcal). Energy expenditure, substrate utilization, and glucose and insulin responses were measured for 4 hr during the postprandial phase. Although postprandial energy expenditure was not affected by prior exercise, the total amount of fat oxidized was higher during Ex+D than during D (170.8 ± 60.1 g vs. 137.8 ± 50.8 g, p < .05), and, accordingly, the use of carbohydrate as substrate was decreased (136.4 ± 45.2 g vs. 164.0 ± 42.9 g, p < .05). After the protein meal fat-oxidation rates were higher than after carbohydrate intake (p < .05), an effect independent of prior exercise. Plasma insulin tended to be lower during Ex+D (p = .072) and after the protein meal (p = .066). No statistically significant change in postprandial blood glucose was induced by prior exercise. Exercising before meal consumption can result in a marked increase in fat oxidation, which is independent of the type of meal consumed.
Metabolism and Whole-Body Fat Oxidation Following Postexercise Carbohydrate or Protein Intake
Ulrika Andersson-Hall, Stefan Pettersson, Fredrik Edin, Anders Pedersen, Daniel Malmodin, and Klavs Madsen
; Morton et al., 2010 ), and exercise-induced immunosuppression ( Gleeson, 2016 ). Ingesting protein in the recovery phase between sessions could potentially be a beneficial strategy to recover immune function ( Cruzat et al., 2014 ) and muscle force capacity ( Buckley et al., 2010 ), and to counteract
Protein Supplements: Do They Alter Dietary Intakes?
Alistair R. Mallard, Rebecca T. McLay-Cooke, and Nancy J. Rehrer
Effects of protein versus mixed macronutrient supplementation on total energy intake (TEI) and protein intake during an ad libitum diet were examined. Trained males undertook two, 2-week dietary interventions which were randomized, double blinded, and separated by 2 weeks. These were high-protein supplementation (HP: 1034.5 kJ energy, 29.6 g protein, 8.7 g fat and 12.3 g CHO) and standard meal supplementation (SM: 1039 kJ energy, 9.9 g protein, 9.5 g fat, and 29.4 g CHO) consumed daily following a week of baseline measures. Eighteen participants finished both interventions and one only completed HP. TEI (mean ± SD) was not different between baseline (11148 ± 3347 kJ) and HP (10705 ± 3143 kJ) nor between baseline and SM (12381 ± 3877 kJ), however, TEI was greater with SM than HP (923 ± 4015 kJ p = .043). Protein intake (%TEI) was greater with HP (22.4 ±6.2%) than baseline (19.4 ± 5.4%; p = .008) but not SM (20.0 ± 5.0%). No differences in absolute daily protein intake were found. Absolute CHO intake was greater with SM than HP (52.0 ± 89.5 g, p = .006). No differences in fat intake were found. Body mass did not change between baseline (82.7 ± 11.2 kg) and either HP (83.1 ± 11.7 kg) or SM (82.9 ± 11.0 kg). Protein supplementation increases the relative proportion of protein in the diet, but doesn’t increase the absolute amount of total protein or energy consumed. Thus some compensation by a reduction in other foods occurs. This is in contrast to a mixed nutrient supplement, which does not alter the proportion of protein consumed but does increase TEI.
Effect of Protein Supplementation Combined With Resistance Training in Gait Speed in Older Adults: A Systematic Review and Meta-Analysis of Randomized Controlled Trials
Juan Li, Yahai Wang, Fang Liu, and Yu Miao
and improving gait speed ( Candow, 2008 ). In addition, some suggest that exercising muscles become more sensitive to nutrients, allowing more available amino acids to be synthesized into muscle proteins. The nutritional consensus statement suggested that consuming protein ranging from 1.2 to 1.5 g
Whey Protein Augments Leucinemia and Postexercise p70S6K1 Activity Compared With a Hydrolyzed Collagen Blend When in Recovery From Training With Low Carbohydrate Availability
Samuel G. Impey, Kelly M. Hammond, Robert Naughton, Carl Langan-Evans, Sam O. Shepherd, Adam P. Sharples, Jessica Cegielski, Kenneth Smith, Stewart Jeromson, David L. Hamilton, Graeme L. Close, and James P. Morton
The role of increased dietary protein intake in facilitating skeletal muscle adaptations associated with endurance training is now gaining acceptance ( Moore et al., 2014 ). Indeed, consuming protein before ( Coffey et al., 2011 ), during ( Hulston et al., 2011 ), and/or after ( Rowlands et
