The recommended dietary allowance (RDA) is 0.8g/lb or 1.76g/kg of body weight daily. This is about 10-35% of the total energy that we consume. Most endurance athletes increase their protein intake to about 1.3g/lb or 2.86g/kg a day to support the balance of nitrogen. BCAA’s or Branched Chain Amino Acids are the primary protein energy source for these endurance athletes. High-intensity strength training could increase the protein requirements by up to 1.7g/lb or 3.74g/kg a day.
Protein as a Source of Energy
One gram of protein supplies 4 kilocalories of energy, which is similar to carbohydrates. However, even though they are similar, protein generally provides less than 5% of the energy expended during light exercise and activities of daily living.
Effects on Sports Performance
There have been studies that show that consuming proteins and amino acids around the time strength and endurance exercises are done can help maintain and potentially even increase skeletal muscle mass. In contrast, protein and amino acid supplementations have not been proven to enhance overall athletic performance. It is also known that high quality proteins such as casein, soy, and whey are effective in skeletal muscle gain and repair. The quality of these proteins is determined by their amino acid composition and their digestibility. Animal proteins are considered complete, high quality proteins because they contain all of the nine essential amino acids. Soybean products are equivalent, but lack one of the amino acids. They are especially important for vegetarians or others with a restricted diet.
Optimum Timing of Protein Intake
Protein intake should generally be spread throughout the day so the body has an opportunity to use the necessary amino acids throughout the day rather than convert them to fat. Protein ingested before a workout, however, may cause some stomach discomfort in some individuals. It could, however, serve as an exercise fuel and in small amounts could even have a muscle-sparing effect which can conserve muscle tissue which could aid in the recovery process post-workout.
Dietary Sources of Protein
There are four forms in which amino acids can be introduced to the body:
- Whole-Food Proteins
- Intact Protein Supplements
- Free-form amino acids
- Protein hydrosolates
When protein is "hydrolyzed" it is made into smaller versions of the protein which is easily digested by the body. Due to this, protein hydrosolate containing sports drinks can be beneficial post-workout. There are other ways to introduce protein into the diet such as adding 1/4 cup of nonfat dry milk (11g of protein) to either fruit smoothies, milk, cereal, pasta, soup, or even sauce. Protein shakes can even be made using the milk and instant breakfast packets.
Isn't More Protein Better Than Less?
Having too much protein is unnecessary and can even be harmful to health. High-protein diets can compromise the carbohydrate status and contribute to dehydration, kidney and liver stress, weight gain, and even urinary loss of calcium. Protein taken in excess does not significantly enhance muscle gains or improve sports performance either. Instead, excess protein can likely turn into fat.
Carbohydrate Plus Protein Speeds Recovery
Combining proteins and carbohydrates in the post-workout meal which is eaten within two hours can help recovery. The ideal carbohydrate to protein ratio is 4:1 g. Excessive protein intake without carbohydrates can actually slow recovery.
Protein is essential to any athlete's diet, however, as seen, it is not a primary energy source. Even for heavy trainers and athletes, excessive protein intake is unnecessary. There are a wide variety of natural protein sources. Protein should be consumed throughout the day. Consuming carbohydrates with proteins can be beneficial for recovery, especially for endurance athletes. Further research is needed to determine the effects of protein intake on exercise performance, overall health, and recovery in the athletic population.
- Benjamin, H. (2010). Protein In the Athlete's Diet. In L. Micheli (Ed.),Encyclopedia of Sports Medicine (pp. 1159-1162). Thousand Oaks: SAGE Publications.