Proteins for Exercise and Fitness
With all the buzz about increasing protein intake, its critical roles in our bodies are often lost. For example, proteins are responsible for body growth, blood clotting, nutrient transport, tissue repair, synthesis of enzymes, antibodies, hormones, and hemoglobin, and regulation of electrolyte and pH levels, among countless other functions. In regards to fitness, protein is used to assemble muscle and will be used as an energy source once carbohydrate stores are depleted for a long period of time.
The myriad and diverse roles of protein can be attributed to their structural design. Proteins are composed of amino acids, whose sequence, folding, and interactions with other amino acids can create the potential for literally limitless unique proteins.
There are two groups of amino acids:
non-essential amino acids, which are produced in the body, and essential amino
acids, which cannot be naturally synthesized in humans. Instead, we obtain essential amino acids
through the food in our diet.
Foods that contain all the essential amino acids we need are classified as `Complete Proteins`. These include food from animals, such as meats, dairy products, eggs and fish. `Incomplete Proteins`, such as vegetables, grains, legumes and nuts, can be eaten with a variety of other foods to provide the full set of essential amino acids.
Athletes and Protein: How much do they need?
The average person will consume approximately 75 grams of protein a day (0.8-1.0 grams/kg body mass) to satisfy the daily nutrient requirement. In contrast, athletes, especially at the professional level will require much more protein to maintain their muscle physique and fitness.
Endurance athletes (ex. long distance runners/bikers) need 1.2-1.4 grams protein/kg body mass. Power athletes (ex. sprinters, swimmers, weight-lifters) will need about 1.2-1.8 grams protein/kg body mass.
While protein obviously plays a significant role in muscle building and repair, one should not consume too much protein. An excess of protein can lead to fluid imbalance (bloating), calcium excretion, kidney or liver damage, and weight-grain.
