The Need for Protein When Exercising

Protein plays a critical role in exercise and athletic performance. It is essential for muscle repair, recovery, and growth, making it a key nutrient for athletes and fitness enthusiasts. Understanding how much protein the body needs and how much it can absorb at one time can help optimize training outcomes.

Why Protein is Important for Exercising Athletes

When you exercise, especially during resistance training or high-intensity workouts, muscle fibers experience microscopic damage. Protein provides the building blocks—amino acids—needed to repair and rebuild these fibers, leading to muscle growth and increased strength. It also supports immune function and hormone production, which are vital for overall health and recovery.

How Much Protein Do Athletes Need?

Protein needs vary depending on the type, intensity, and duration of exercise, as well as the athlete's body weight and goals. Current research suggests the following general guidelines:

- Endurance athletes: 1.2 to 1.4 grams of protein per kilogram (1 kg = 2.2 lbs) of body weight per day

- Strength athletes: 1.6 to 2.2 grams of protein per kilogram of body weight per day

For example, a 70 kg (154 lbs) strength athlete might aim for 112 to 154 grams of protein daily.

Protein Absorption: How Much Can the Body Use at One Time?

There is a common misconception that the body can only absorb a limited amount of protein (e.g., 20-30 grams) per meal. While the intestines can absorb nearly all consumed protein, the rate at which amino acids are utilized for muscle protein synthesis (MPS) is what's more relevant.

Research indicates that consuming about 20-30 grams of high-quality protein per meal maximizes MPS in young adults. Intakes beyond this might be oxidized for energy or used for other bodily functions rather than muscle building. However, this can vary based on age, exercise type, and overall dietary context.

Practical Takeaways

- Distribute protein intake evenly across meals to optimize muscle repair and growth.

- Athletes should focus on total daily protein intake aligned with their sport and training intensity.

- Include a variety of high-quality protein sources such as lean meats, dairy, eggs, legumes, and plant-based proteins.

- Remember hydration and overall balanced nutrition play essential roles in recovery and performance.

Protein Study Links

- Tipton, K. D., & Wolfe, R. R. (2004). Protein and amino acids for athletes. Journal of Sports Sciences, 22(1), 65-79. https://doi.org/10.1080/0264041031000140554

- Phillips, S. M., & Van Loon, L. J. (2011). Dietary protein for athletes: from requirements to optimum adaptation. Journal of Sports Sciences, 29(sup1), S29-S38. https://doi.org/10.1080/02640414.2011.619204

- Morton, R. W., et al. (2018). A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine, 52(6), 376-384. https://bjsm.bmj.com/content/52/6/376

- Areta, J. L., et al. (2013). Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. The Journal of Physiology, 591(9), 2319-2331. https://doi.org/10.1113/jphysiol.2012.244897