There still exists considerable confusion and controversy regarding the protein requirements for athletesparticularly for those who are involved in high-intensity training. Although scientists disagree on precise protein needs, many strength and conditioning professionals who want to enhance muscle mass in athletes have increased their daily protein intake far above the RDA. Many of these confusions are due to poorly-designed research and lack of knowledge about protein metabolism. This results in recommendations that can be harmful and sometimes unnecessary. Complex molecules, proteins, have many structural and enzymatic functions that promote body growth, maintenance and repair. The role of dietary proteins in athletes, fitness enthusiasts, and sedentary individuals is to provide the necessary amino acids for the body’s ability to absorb proteins from skeletal structures, hormones, cell membrane receptors and to maintain fluid balance. Although protein has a 4kilocalories/gram energy content, this contribution may be less than 5-10%. However, it can increase when there is a decrease in energy intake.
Amino acids are the basic building blocks for protein. They contain nitrogen. You can determine the body’s current nitrogen status by subtracting any nitrogen losses (sweats, urine and feces) from your dietary nitrogen intake. Because muscle protein is constantly changing, it’s important to measure the body’s total nitrogen status. In other words, an impaired protein synthesis can cause catabolic (breakdown-predominant) effects, leading to increased nitrogen excretion. Protein can become oxidized or transformed to fat if it is consumed in excess. The balance of a positive and negative nitrogen balances determines the protein content in muscles. This balance promotes growth or building up protein, while catabolism promotes it.
The quality of the protein is key to determining its daily intake. There are 22 different amino acids that are required to make protein. 9 of these are necessary and 13 are not. The body can’t synthesize essential amino acids, so they need to be taken from food. The body can synthesize nonessential amino acid as long as it has sufficient nitrogen. But, the nutrition may also help. To properly synthesize human tissue proteins, one must have sufficient amounts of the essential amino acids. Complemented proteins are those that have all necessary amino acid. These proteins can be obtained from meat, fish or dairy products. Complete proteins are missing one or more essential amino acids. They can be found in plant foods like nuts, grains and legumes. This means that you need to consume a varied diet rich in protein. Vegetarians could be deficient in some essential amino acid and may need to supplement their diet.