Research Supports Nutrient Timing for Muscle Growth

Proven Effects of Nutrient Timing on Muscle

In a prior article for contest preparation, I simplified caloric intake and macronutrients from the recent evidence-based guidelines published by the Journal of the International Society of Sports Nutrition. I advise reading part 1 and get the food information down before moving onto the next category of nutrient timing. Nutrient timing is not about meal frequency, but getting down to the minute of when nutrients should be consumed during or after a workout specific to contest-prep. Natural bodybuilders put extreme effort into sculpting muscle and are trying to maintain lean body mass (LBM) through precise timing of nutrient intake. This is another area where research has not effectively answered the call to consuming nutrients, especially proteins during training. Most of the studies have been conducted on endurance athletes where glycogen stores are completely depleted leaving the muscles starving for nutrient attention. We have all heard to refuel immediately after exercise which may hold true for some athletes, but let’s look into what science is now saying about contest-prep nutrient timing for natural bodybuilders.

Nutrient Timing and Research

Nutrient Timing
Achieve a Stage Ready Body with Nutrient Timing. mihailomilovanovic/Getty Images

The challenge for me is educating you on nutrient timing in an entertaining short version of the study which is completely awesome. Workouts for bodybuilders are quite different to let say a marathon runner and are not usually glycogen depleting. Glycogen is simply energy stored in our muscles and body used to perform work. Research shows high intensity resistance training at least 70-80% of 1 rep max (RM) at a moderate rate of 6-9 sets per muscle group. This reduces glycogen levels by approximately 39% and preserving some stores.  Continuing studies indicate consuming protein or amino acids and carbohydrates in combination near or during training have a positive effect on muscle protein synthesis (muscle growth) and reduction of muscle protein breakdown. This is great news, however only a handful of studies are supporting nutrient timing as the reason for muscle preservation. During a 10-week resistance training program where subjects supplemented with 20g of protein and amino acids one hour pre and post-workout increased muscle protein synthesis (MPS) and strength compared to a carbohydrate placebo. Another 21-week study where 15g of whey protein was supplemented pre and post-workout showed an increase in muscle size of the quadriceps.  

Nutrient Timing Narrowed Down

Nutrient Timing and Contest Prep
Timing Protein and Carb Nutrients are Important for Bodybuilders. Arthur Kwiatkowski E+/Getty Images

Great news for contest-prep natural bodybuilders but science will still throw curve balls. For every favorable finding, there will also be an opposing result. The inconsistencies come from studies not providing the same research environment with participants. Value or even type of nutrients consumed along with differing time tables are factors. Some researchers indicate studies are lacking sufficient protein doses to support muscle protein synthesis (MPS) as the reason for negative outcomes. There is also a question of protein and carbohydrate combinations lacking in research and their role in MPS or muscle growth. On the positive side, chronic research has narrowed down recommendations for nutrient timing.    

Nutrient Timing Recommendations

Nutrient Timing and Contest Prep
Nutrient Timing is Practical Application of all Macronutrients. Cultura RM/Corey Jenkins/Getty Images

Contest prep is tough work and natural bodybuilding, although extreme in physical training is generally short in duration. Because of this, glycogen is preserved through workouts. If a healthy meal was consumed prior to resistance training, research indicates nutrients during training aren't necessary. However, if an intense exhaustive resistance training workout exceeds 2-hours, it's recommended "approximately 8–15 g protein co-ingested with 30–60 g carbohydrate in a 6-8% solution per hour of training” be consumed. It really comes down to practical application for muscle preservation. What is further advised in a recent study by Aragon and Schoenfeld is to consume protein at .4 to .5g/kg of body weight pre and post-workout. Concluding the segment on nutrient timing is the statement “current evidence indicates that the global macronutrient composition of the diet is likely the most important nutritional variable related to chronic training adaptations.” In other words, it will still be the combination of all macronutrients consumed throughout the day giving the best chance for a stage ready body.

Sources:

Journal of the International Society of Sports Nutrition, Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation, Eric R Helms et al., 5/12/14

Journal of Applied Physiology, Muscle glycogen synthesis after exercise: effect of time of carbohydrate ingestion, J. L. Ivy et al., 4/1/88

Journal of Applied Physiology, Muscle glycogenolysis during differing intensities of weight-resistance exercise, R. A. Robergs et al., 4/1/91

Journal of Applied Physiology, Influence of differing macronutrient intakes on muscle glycogen resynthesis after resistance exercise, B. D. Roy et al., 3/1/98

Journal of Strength and Conditioning Research, The effect of a carbohydrate and protein supplement on resistance exercise performance, hormonal response, and muscle damage, Baty JJ et al., 5/07

American Journal of Physiology, Endocrinology and Metabolism, Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise, Tipton KD et al., 8/01

Journal of Physiology, Timing of postexercise protein intake is important for muscle hypertrophy with resistance training in elderly humans, Esmarck B et al., 8/01

Journal of the International Society of Sports Nutrition, position stand: Nutrient timing, Chad Kerksick et al., 10/3/08

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