Protein Function

The most highlighted and important protein function is to build and repair tissue. That’s a pretty important function! When in the life-cycle would you build the most tissue? During periods of rapid growth and development. In infancy, babies can triple their birth weight in their first year of life. Because of that, babies have a really high protein need. When you have surgery (where doctors intentionally create damage to your tissue), you need extra protein to repair it. Oftentimes what people believe, however, is that when they’re laying flat on the bed after surgery they don’t need as many calories or protein. Physiologically that’s not true. Your needs for both of those go up significantly.

Another protein function is to hold your body together and let you move it. When muscular contraction happens proteins are sliding over each other. One of the reasons why athletes prefer a high-protein diet is because they want to create more of these sliding proteins (and hence have more strength).

In the process of weight lifting you are trying to increase the mechanical strength of those proteins. When you lift heavy enough weights these proteins tear, and when you rest (specially during sleep), more amino-acids are going to get to the damaged proteins and cause the muscle to get bigger.

We also know that we need protein for the immune function. Protein has a function in the synthesis of enzymes. Enzymes are compounds that accelerate chemical reactions. For example, lactase is the enzyme that helps to digest milk sugar. Also, hormones are proteins which act as chemical messengers produced in one part of the body but used in another.

Another protein function is to serve as transports. They transport drugs, vitamins and minerals throughout our body.

An important protein function is to balance fluid distribution in your body. Protein prevents fluid in your blood from leaking into the non-vascular space between cells. With inadequate amounts of protein, that water can leak from your blood into your tissues. This means you will gain weight!

Protein is a source of energy. However, it shouldn’t be used as a primary source. It is your body's least favorite fuel. Your body can use protein as an energy source (4 calories a gram), but that’s not its primary intent. Protein has to accomplish all those wonderful things I listed above. However, if I don’t take in adequate amounts of carbohydrate, protein is going to be sent to the liver and turned into carbohydrate.

One of the biggest mistakes people make in the athletic world is trying to replace carbohydrates with protein. They don’t realize that they are causing their body to take very expensive protein and sent it to their liver to get carbohydrates! Protein is designed for the building and repairing of tissue. You don’t need to use it as an energy source. However, if you use it for energy, it’s like trying to heat your house using 100 dollars bills as fuel. That’s what you do when you don’t take adequate amounts of carbohydrates and a lot of protein.

Protein can also help in weight management as it leaves your stomach slowly. What that does is to create a sense of fullness. At the grocery store you would see breakfast cereals aimed at weight management with added protein. They add it to promote that feeling of fullness.

In order to get all of this work done, the body needs a daily supply of amino-acids to make new protein. We don’t store protein. We can an endless ability to store fat and a small ability to store carbohydrate in our muscles and liver. We can’t, however, store protein. If we can’t store it, any loss of body protein is going to represent loss of function. This means your body can't accomplish all those things I listed! If you don’t consistently replenish protein on a daily basis, you will lose protein from some part of our body and that can represent loss of function.