Proteins are important for many vital functions in your body. Not only do they provide the building blocks for muscles, tendons and all other soft tissues, but they also play a key role in making hormones, enzymes and neurotransmitters (1). 

Proteins are made from 21 different amino acids. Nine of them cannot be produced by your body and must come from your diet. They are called essential amino acids and high-quality proteins provide all of the essential amino acids in relevant amounts (1).

Exercise and the Importance of Protein

Dietary protein is important in relation to exercise for various reasons. As well as providing building blocks, essential amino acids (particularly leucine) also serve as a signal to start the process of muscle protein synthesis. They help to build the proteins involved in energy metabolism and enable structural changes to tendons and bones (2-4).

When you do not consume enough protein, more protein gets broken down than built, which slows down recovery and increases your risk of injury and illness. Protein consumption is needed to build new proteins, replace damaged ones in our muscles and other tissues and support other changes. Over time this will help your body adapt to the specific demands of your training program, making you a better athlete (2, 5, 6).

Protein Intake Recommendations

Athletes and individuals with an active lifestyle need to consume more protein than people who do not regularly exercise. The current guidelines recommend that you consume of 1.2-2.0 g of protein per kilogram of bodyweight per day (2, 5, 7).

After exercise, muscle protein synthesis peaks within 3 hours and remains elevated for at least 24 hours. Protein intake can also stimulate muscle proteins synthesis, but only for about 4 - 5 hours. In order to optimise the muscle-building process after exercise, athletes are recommended to consume 20 - 40 g of high-quality protein in 4-6 meals throughout the day (2, 5, 6, 8).

What are some High-Quality Protein Sources?

Good sources of high-quality protein include lean meats such as poultry and fish, milk and milk products (which provide both casein and whey protein), eggs and protein supplements such as shakes and bars. Most plant proteins, with some exceptions like soy, are of a lower quality and have a lower leucine content than proteins from animal foods. However, protein quality can be improved by mixing various plant sources in a meal. Good sources of plant protein include grains, quinoa, legumes, nuts and plant-based protein shakes (1, 4, 6, 9). 

Athletes and individuals with an active lifestyle have higher protein requirements, as the exercise they do places large demands on their bodies. Including high-quality protein sources at every meal helps your body adapt and recover, leaving you better prepared for your next workout.

References

1. EFSA Panel on Dietetic Products N, Allergies. Scientific Opinion on Dietary Reference Values for protein. EFSA Journal. 2012;10(2):2557.
2. Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance. Med Sci Sports Exerc. 2016;48(3):543-68.
3. Devries MC, Phillips SM. Supplemental protein in support of muscle mass and health: advantage whey. J Food Sci. 2015;80 Suppl 1:A8-a15.
4. van Vliet S, Burd NA, van Loon LJ. The Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein Consumption. J Nutr. 2015;145(9):1981-91.
5. Jäger R, Kerksick CM, Campbell BI, Cribb PJ, Wells SD, Skwiat TM, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
6. Kerksick CM, Wilborn CD, Roberts MD, Smith-Ryan A, Kleiner SM, Jäger R, et al. ISSN exercise & sports nutrition review update: research & recommendations. J Int Soc Sports Nutr. 2018;15(1):38.
7. Phillips SM, Chevalier S, Leidy HJ. Protein "requirements" beyond the RDA: implications for optimizing health. Appl Physiol Nutr Metab. 2016;41(5):565-72.
8. Burke LM, Hawley JA. Swifter, higher, stronger: What's on the menu? Science. 2018;362(6416):781-7.
9. Bytomski JR. Fueling for Performance. Sports Health. 2018;10(1):47-53.