What Is the Relationship between Protein and Muscle Building?

There is an essential link between the consumption of dietary protein and muscle building, a cause-and-effect relationship that must be understood in order to optimally attain increased muscle mass. Protein is the macronutrient that is responsible for tissue-building and repair. The strength training that must be performed to develop one’s muscles results in the formation, temporarily, of microscopic tears in muscle fiber. Protein stimulates the healing process, which in turn produces muscles that are stronger and, depending on the training protocol and diet followed, bigger.

It is widely understood that in order to build muscle, physical exercise like weightlifting that challenges existing muscle must be performed regularly. Strength training, however, is a catabolic process, meaning that this type of exercise breaks down rather than builds muscle tissue. In order to increase performance and see improved physical results, proper nutrition is fundamental to the process. This is where protein and muscle building come together.

Protein is one of three nutrients, along with carbohydrates and fat, called macronutrients that supply the body with calories. Unlike carbs and fat, however, protein is rarely used for energy and is therefore not stored by the body. Though the cells can synthesize some of the amino acids the body needs, most of these must be obtained through protein in the diet. The consumption of protein and muscle building, then, are complementary processes, as protein is necessary for anabolism, or the building of tissue.

When protein is consumed through foods like eggs, meat, dairy, and beans, it is broken down by enzymes in the stomach into its amino acid components, amino acids like isoleucine and glutamine. These are largely absorbed in the intestines, with absorption rates varying depending on the type of proteins consumed. In fact, different protein sources are assigned a biological value (BV), which represents the percentage of protein absorbed from a given food that will be integrated with the body’s existing proteins. When considering the relationship between protein and muscle building, BV can be a helpful guideline for determining which protein sources will best promote muscle growth.

Though values can vary depending on how a food is prepared, most whole foods can be assigned a typical BV, which can in turn determine what protein sources are most useful to an individual wishing to build muscle. With the listed values representing an approximate percentage of the absorbed proteins that will be utilized by the body, some examples of optimally utilized foods for mass building include whey protein, with a BV of 96; whole soybeans, with a BV of 96; cow’s milk, with a BV of 95; and chicken eggs, with a BV of 94. The combination of the consumption of high-BV protein and muscle-building exercises performed on a regular basis has been shown to be effective at producing increases in lean mass.