Protein: you hear a lot about it and you know it's important. Learn why it's essential to good health and good eating.
Proteins, along with fats and carbohydrates, are the macronutrients that form the basis of our diets. Once consumed, some people associate protein only with helping to build muscle, but keep in mind that's not all it does for us. In our bodies protein performs a range of duties, from building new cells to regulating metabolism to helping cells communicate. Proteins help shuttle oxygen throughout the body in the form of hemoglobin, as well as build muscle.
Dietary protein provides us with energy (calories). Like carbohydrates, protein contributes 4 calories per gram, versus 9 calories per gram in fats and 7 calories per gram in alcohol.
For many people, upping the amount of protein in the diet may help manage weight and improve body composition — learn more about Protein & Weight Loss.
Amino acids are the building blocks of proteins. Our DNA directs the body to join various combinations of amino acids into a variety of sequences and three-dimensional shapes for an arsenal of over 2 million different proteins, each serving a unique function. Our bodies can make some of these amino acids, but there are nine that are considered "essential amino acids" because we must consume these through our diet.
While our bodies can store fats and carbohydrates to draw on when needed, we do not have a storage pool of amino acids. We need a fresh source each day in order to build the body proteins we need. If the body is missing a particular amino acid to form the protein it needs, it will pull that amino acid by breaking down existing muscle protein. If we consistently lack certain amino acids we will lose muscle weight, energy and, eventually, fundamental functions.
The amount of protein you need depends on your weight and health. The Recommended Daily Allowance (RDA) for protein for the healthy individual is 0.8 grams of protein per kilogram of body weight or 3 to 4 grams per 10 pounds, and two to three servings of protein-rich food will meet the daily needs of most adults. Athlete's protein intake recommendations may be higher.
Protein, and the essential amino acids our body needs, can be found in an abundance of foods and beverages, including both plant and animal sources. Here are the main sources of dietary protein: