Protein is an essential nutrient that is used in the body for the growth and repair of cells and to provide energy.
You can get energy from protein, but it’s not your best choice. Protein has other functions that take priority over using it as an energy source. Building muscles and producing the protein-based substances that make muscles contract for example. It also takes your body longer to turn protein into energy compared to the quick boost you can get from carbohydrates.
When the proteins you eat are digested, they’re broken down into individual amino acids so that cells in your body have access to whichever ones they need for the job at hand. About 75 percent of amino acids are used to synthesize new proteins. These proteins help build and repair tissues, including muscles, bones and skin. They’re also used to produce enzymes that digest food and activate your metabolism.
Amino acids are chemically similar to glucose except that they contain nitrogen. After protein is digested into amino acids, they must go through more steps to have the nitrogen removed. Once the nitrogen is gone, the amino acids are converted into glucose or fatty acids. Either way, they give you energy.
Protein is found in both plant and animal foods. Sources of protein include meat, eggs, dairy foods, nuts and seeds, dried beans and lentils.