Protein: The Building Blocks of Muscle
It’s about time we rounded out our discussion on nutrients with a very important one – Protein. Protein is not only the building block of muscle, it’s also used for energy…in some cases.
The Importance of Protein
Proteins are involved in much of the body’s sustainment, including growth, repair, and tissue replacement. They help form skin, tendons, muscles, organs, and bones. On occasion, proteins also have an additional role of providing fuel for the body when energy from carbohydrates is not available.
Protein is made up of amino acids. Within the body, proteins are constantly being produced and broken down. When you take protein supplements or eat foods containing protein, these proteins are broken down into amino acids for absorption. The amino acids are then collected in cells and in the bloodstream. The body then uses these amino acids for energy or to create its own protein. In all, there are 20 amino acids, 9 of which are deemed “essential” (meaning the body cannot produce them or cannot produce enough of them on its own).
Energy from Protein
Remember that the body’s primary energy source comes from carbohydrates. Fats also provide energy at certain times. The same is true with protein, only to a lesser extent. Amino acids are used for energy only when glucose (from carbohydrates) and fatty acids are limited. In effect, proteins and amino acids are the body’s third and final choice to meet its energy requirements.
In order for the body to use protein as an energy source, it must break down tissue. This is why lean body tissue is lost over periods of long starvation, when there is no intake of carbs or fats. Therefore, in order to preserve lean tissue mass, adequate supplies of carbs and fats must be available to the body. Similarly, in order to grow lean tissue mass (muscle) adequate amounts of protein must be consumed.
Which Proteins Should I Eat?
You should look for protein sources that don’t contain excess fat. Natural protein sources such as lean meats, milk, eggs, and legumes provide all of the protein and amino acids the body needs in the correct ratios and proportions.
Besides looking for nutrient dense proteins, we should also look for high-quality proteins. High quality proteins contain all 9 essential amino acids. Most animal proteins are high-quality.
The USDA recommends that 10-35 percent of total intake come from protein. The important thing to remember is that a balanced diet with a variety of food choices should provide all of the body’s protein needs.