Build Muscle All Day & While You Sleep

Nutritional Guide to Optimum Growth

Muscle 24/7

 Muscle cells get bigger and stronger from heavy resistance training, basically by increasing the amount of protein molecules within each and every muscle cell. They synthesize more protein molecules in response to weightlifting, primarily because protein molecules perform many key cellular functions that are essential in order to exercise. Muscle cells adapt to exercise stress by increasing the level and therefore, the activity of, these specific protein molecules— thus enhancing exercise performance. Up to this point, it has been pretty well established that resistance exercise followed by amino acid consumption effectively triggers muscle growth by activating muscle protein synthesis. However, recent scientific research demonstrates some novel ways to consume amino acids after exercise that further increase muscle protein synthesis— representing powerful approaches that further enhance muscle growth and strength.

Carbs After Exercise Decrease Protein Catabolism

 Maximizing muscle growth stems from increased muscle protein synthesis while decreasing muscle protein breakdown, creating a positive protein balance within the muscle cell. Unfortunately, lifting weights typically increases muscle protein synthesis but also tends to increase muscle protein breakdown. However, the consumption of certain macronutrients after your workout can decidedly improve muscle protein balance. For example, carbohydrate consumption after pumping iron has been shown to improve protein balance by decreasing the level of protein degradation.¹ A study by Roy et al.² observed that consuming 1 gram of carbohydrate per kilogram of bodyweight, during and one hour after resistance exercise, slightly decreased muscle protein breakdown. Unfortunately, this small decrease in protein degradation does not significantly improve muscle protein synthesis or overall net protein balance. The rationale for carbohydrates solely influencing protein degradation most likely comes from the increased cellular energy from carbohydrate consumption, which turns off the protein degradation triggered by the enzyme AMPK. AMPK is the muscle cell’s energy gauge that promotes the breakdown of protein into amino acids when cellular energy is low, so the amino acids can be subsequently burned to restore cellular energy. Consequently, carbohydrate consumption during exercise should mitigate the AMPK-driven breakdown of muscle protein.

Amino Acids Increase Muscle Protein Synthesis   

 Although carbohydrate consumption only influences muscle protein breakdown and does not lead to an overall increase in muscle protein, ingesting of amino acids— especially leucine— directly after resistance exercise significantly improves protein synthesis while somewhat decreasing protein degradation— yielding a net positive balance. Amino acid consumption causes muscle protein accumulation mainly by activating the extremely important nutrient-sensing molecule mTOR, which directly activates muscle protein synthesis in response to amino acid consumption. Additionally, mTOR also prevents muscle protein breakdown by inhibiting AMPK's catabolic influence on protein levels within the muscle cell.

 Demonstrating the importance that amino acid consumption has on mTOR activity, a study Walker et al.³ established that ingesting essential amino acids shortly after working out increased mTOR activity— leading to greater post-workout muscle protein synthesis and decreased protein degradation for an additional two hours, compared to an exercised group that was not fed essential amino acids.

Amino Acids + Carbs Greatly Increase Muscle Protein Levels

 Because carbohydrates decrease protein degradation and amino acids activate protein synthesis, the simultaneous consumption of carbohydrates and amino acids should generate an even greater accumulation of muscle protein levels by increasing protein synthesis while inhibiting protein degradation. In order to investigate the additive influence of carbohydrates and amino acids on muscle protein levels, Miller et al.⁴ confirmed that the consumption of essential amino acids plus carbohydrate has a much greater positive impact on muscle protein synthesis while decreasing protein degradation, compared to ingesting essential amino acids or carbohydrates alone. Interestingly, as I previously mentioned, carbohydrate ingestion diminishes AMPK’s ability to degrade protein while amino acid consumption turns on mTOR-driven protein synthesis. Since AMPK has been shown to inhibit mTOR, carbohydrate inactivation of AMPK should further activate mTOR— perhaps explaining to some degree the synergistic activation of muscle protein synthesis from carbohydrate and amino acid consumption that Miller et al. demonstrated in their study.

Weightlifting Increases Muscle Protein Synthesis

 Although amino acid’s post-exercise stimulation of muscle protein synthesis only lasts a few hours, muscular contraction associated with intense weightlifting produces increases in muscle protein synthesis that may be sustained for up to 24 hours. Therefore, consumption of amino acids within 24 hours post-exercise should also impart a stimulatory influence on muscle protein synthesis, as observed when amino acids are provided immediately after resistance exercise.^5,6

 In order to investigate whether consuming amino acids over 24 hours enhanced muscle protein synthesis, a study by Burd et al. showed that feeding 15 grams of whey protein 24 hours after resistance exercise resulted in a greater stimulation of muscle protein synthesis than the same dose provided without exercise.⁷

 Another study by Res et al.⁸ assessed the influence of consuming amino acids right before going to sleep after weightlifting that same day. The study looked at healthy, young males split into two groups with one group receiving 40 grams of casein protein right before bed, while the control group received a placebo with no casein. The group that received casein protein showed a rapid rise in amino acid levels in the blood that corresponded to an increase in muscle protein synthesis that was 22 percent greater than the placebo group. More importantly, the casein-ingesting group also showed an improved net protein balance— demonstrating that consuming protein well after exercise still enhances muscle protein levels, providing an environment that should lead to greater muscle growth and strength.

 In conclusion, consuming carbohydrates to mitigate muscle protein degradation in combination with protein/amino acids immediately and up to 24 hours following exercise should be considered a nutritional strategy that maximally stimulates exercise-induced muscle protein synthesis— leading to superior levels of muscle growth not only throughout the day, but even while you sleep.

For most of Michael Rudolph’s career he has been engrossed in the exercise world as either an athlete (he played college football at Hofstra University), personal trainer or as a Research Scientist (he earned a B.Sc. in Exercise Science at Hofstra University and a Ph.D. in Biochemistry and Molecular Biology from Stony Brook University). After earning his Ph.D., Michael investigated the molecular biology of exercise as a fellow at Harvard Medical School and Columbia University for over eight years. That research contributed seminally to understanding the function of the incredibly important cellular energy sensor AMPK— leading to numerous publications in peer-reviewed journals including the journal Nature. Michael is currently a scientist working at the New York Structural Biology Center doing contract work for the Department of Defense on a project involving national security.

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