The purpose of this review was to determine whether past research provides conclusive evidence about the effects of type and timing of ingestion of specific sources of
protein by those engaged in resistance weight training. Two essential, nutrition-related, tenets need to be followed by weightlifters to maximize muscle
hypertrophy: the consumption of 1.2-2.0
g protein.kg -1 of
body weight, and ≥44-50 kcal.kg-1 of
body weight. Researchers have tested the effects of timing of
protein supplement ingestion on various physical changes in weightlifters. In general,
protein supplementation pre- and post-workout increases physical performance, training session recovery, lean body mass, muscle
hypertrophy, and strength. Specific gains, differ however based on
protein type and amounts. Studies on timing of consumption of milk have indicated that fat-free milk post-workout was effective in promoting increases in lean body mass, strength, muscle
hypertrophy and decreases in body fat. The
leucine content of a
protein source has an impact on
protein synthesis, and affects muscle
hypertrophy. Consumption of 3-4 g of
leucine is needed to promote maximum
protein synthesis. An ideal supplement following resistance exercise should contain
whey protein that provides at least 3 g of
leucine per serving. A combination of a fast-acting
carbohydrate source such as
maltodextrin or
glucose should be consumed with the
protein source, as
leucine cannot modulate
protein synthesis as effectively without the presence of
insulin. Such a supplement post-workout would be most effective in increasing
muscle protein synthesis, resulting in greater muscle
hypertrophy and strength. In contrast, the consumption of
essential amino acids and
dextrose appears to be most effective at evoking
protein synthesis prior to rather than following resistance exercise. To further enhance muscle
hypertrophy and strength, a resistance weight- training program of at least 10-12 weeks with compound movements for both upper and lower body exercises should be followed.