Protein: The Importance of Fueling our Muscles After Exercise

Published on September 04, 2017 by Dr. Aaron Zadek ND

There is a special feeling associated with conquering a challenging workout. As part of an active daily lifestyle, it is important to safely test our body’s boundaries of strength and endurance. This challenge is different for everyone; attempting more weight or repetitions at the gym, extending your long run by a few extra kilometers, or holding onto those new yoga poses as long as possible.  Overcoming these new obstacles leave us with a great sense of accomplishment but also leaves us feeling sore the next day. 

The importance of a proper recovery that includes optimized protein and antioxidant intake, as well as attention to nutrient timing, helps reduce muscle soreness and improve muscle function for future training (Ives, et al., 2017).

How much protein should I have?

Protein is an essential part of our diet and provides the building blocks required for all tissues of the body, including muscle. That said, depending on the type of exercise you enjoy, the amount of protein needed to support your muscles may vary. Both endurance and strength-based exercises increase the body’s demand for protein, specifically branch-chain amino acids including leucine, to help boost repair. These branched chain amino acids are structurally important for stimulating growth and repair in our muscles. Higher protein diets containing more than 1 g/kg body weight are shown to promote healthy aging, improve appetite regulation and weight management (Phillips, Chevalier, & Leidy, 2016). Higher protein intake can also help with improving fat loss and reduction in body weight when combined with exercise and caloric control, and improved immune function.

Are there dangers of consuming too much protein? 

There have been recent studies that have looked at gargantuan protein intakes, equivalent to eating your body weight in protein per day, to determine whether or not there is any health risk associated with increased protein consumption. These studies have shown no adverse health effects, specifically no damage to liver or kidneys and no change in bone health (Antonio, et al., 2015) (Phillips, Chevalier, & Leidy, 2016). While there are certain medical conditions that must adhere to low protein diets, those who are healthy and active will benefit from increased protein consumption, though consumption of 1-1.6 g/kg bodyweight is more realistic.

Should protein intake change with age?

There is new evidence that supports the idea that as we age our muscles do not respond as quickly to protein and that more leucine, a branch chain amino acid, is needed to stimulate adequate recovery (Katsanos, et al. 2006). Many mistake leucine as just another protein building block for muscle. In fact, leucine is responsible for signalling muscle growth and maintaining the integrity of the muscle cellular membrane.  When we are young children our muscles respond quickly to leucine, reflecting our young body’s rapid state of growth. As we age, the need for growth is not as important but our need for recovery is still desired. It has been demonstrated that those 66 years and older have a reduced muscle protein manufacturing response and that to boost recovery more leucine is required. This requirement should be filled through diet as well as healthy supplementation with a clean protein supplement.

What is the best source of protein?

Discussing sources of protein can often lead to heated conversations over the merits of animal verses vegetarian sources. To optimize recovery post-workout, it is important to look at the leucine content in these sources to ensure that you reach the amount needed to stimulate recovery. A serving of protein, regardless of source, should look to deliver 2-3 grams of leucine per serving to maximize muscle repair. This is the equivalent to a 3-4 oz. chicken breast or 2-2.5 cups of lentils.

Animal protein sources such as chicken, fish and whey contain higher leucine content per serving compared to vegetarian sources such as hemp, pea and soy. Your muscles will be just as happy eating animal or vegetarian sources provided you are getting 2-3 grams of leucine per serving. Moral of the story; the source is not as important provided you are getting enough high quality protein through your day (Joy, et al., 2013).

Nutrient timing: 

Timing of protein containing meals is important for recovery from all types of exercise. For 24 hours after exercise, your muscle is most accepting of protein. Repair of skeletal muscle appears to be optimized when 20-30 grams of protein is consumed right after exercise and again every 3-4 hours (Jager, et al., 2017).

Final Thoughts:

Exercise is a crucial component to a happy, healthy life. Ensuring that we recover properly helps ensure that we can continue to do the activities we love more often. While arguments over what is the best protein source exist, the research is very clear, as long as you are consuming protein every 3-4 hours after exercise, and it contains enough leucine, then you are optimizing your recovery.

Select References

Antonio, J., Ellerbroek, A., Silver, T., Orris, S., Scheiner, M., Gonzalez, A., et al. (2015). A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women - a follow up investigation. Journal of the International Society of Sports medicine, 12, 1-9.

Ives, S. J., Bloom, S., Matias, A., Morrow, N., Martins, N., Roh, Y., et al. (2017). Effects of a combined protein and antioxidant supplement on recovery of muscle function and soreness following eccentric exercise. Journal of the International Society of Sports nutrition, 14(21).

Jager, R., Kerksick, C. M., Campbell, B. I., Cribb, P. J., Skwiat, T. M., Purpura, M., et al. (2017). International Society of Sport Nutrition Position Stand: Protein and Exercise. Journal of the International Society of Sports Nutrition, 14(20).

Joy, J. M., Lowery, R. P., Wilson, J. M., Purpura, M., De Souza, E. O., Wilson, S. M., et al. (2013, June 20). Effects of 8 weeks of whey or rice protein supplementation on body composition and exercise performance. Nutrition Journal, 12(1), 86-92.

Katsanos, C., Kobayashi, H., Sheffield-Moore, M., Aarsland, A., & Wolfe, R. (2006, Feb 28). A high proportion of leucine is required for optimal stimulation of the rate of muscle protein synthesis by essential amino acids in the elderly. American journal of physiology. Endocrinology and metabolism., 291(2), 381-387.

Phillips, S. M., Chevalier, S., & Leidy, H. J. (2016). Protein "requirements' beyond the RDA: implications for optimizing health. Applied Physiology, Nutrition and Metabolism, 41(5), 565-572.