NUTRIENTS FOR THE ATHLETE: PROTEIN & AMINO ACIDS

There is a general misunderstanding about the protein needs of athletes. Many believe that large quantities of protein foods are necessary to enhance muscle growth. Amino acid supplementation is not necessary even for body builders. Training techniques and genetics are the critical determinants of muscle size. Extra protein in the diet (in the form of food or amino acid pills) beyond what your body demands for rebuilding and repair doesn’t go to make extra muscle. Protein can’t be stored for later use, if the athletes body gets more protein than it needs, extra is broken down and stored as fat or used as energy.

High protein intakes have never been shown to be uniquely beneficial to athletes.

Intakes of protein > 15% of total calories cannot be justified on a scientific basis. For an individual consuming 4000 calories per day, 15% of calories represent 150 grams of protein or 2 grams/kg body weight for 70-kg male (note RDA is 0.8 grams/kg of body weight/day). This almost exceeds the requirement by 270%.

Intakes above 15% or 2 grams/kg of body weight are either burned for energy to support activity or are converted to fat.

In addition, these processes result in residual nitrogen, which must be discarded through the urine as urea and ketones. This step requires the loss of water, which increases the athlete’s chance of dehydration. Excessive protein intake (5 times the RDA) can also cause a loss of bone calcium and can also put strain on the liver and kidneys.

Protein is the toughest nutrient to digest. Your body expends a lot of energy just breaking down high protein foods. Therefore high protein foods should be avoided before training.

Contrary to popular opinion, muscle size is not dependent on protein intake. If daily minimum intakes are met, muscle size will be dictated by the specific training demands and of course genetic potential.

Protein can be supplied from animal food sources, such as lean meat, poultry, fish, eggs, milk, and cheese, or vegetable food sources such as dried beans and peas, peanut butter, nuts, seeds, and tofu. Breads, cereals and vegetables contribute small amounts of protein in the diet. Plant protein from vegetable sources is usually low in one or more of the nine essential amino acids. Vegetable protein sources, in combination, can complement one another to provide a high-quality protein.