Nutrition Of Protein In Foods

Proteins are a type of macronutrient that provides the structural foundation to almost every cell in your body. Each protein consists of a series of amino acids. The proteins in your body perform a wide range of functions. To ensure your body contains enough protein to function properly, it is important that you consume enough protein in your diet.

Functions of Protein

Because they contain calories, proteins can provide you with energy. "Nutrition and You" by Joan Salge Blake notes that you should not rely on protein as an energy source, however, because this prevents the protein in your body from performing its other important functions.

The proteins in your body maintain acid-base balance, help build enzymes and hormones, and transport various substances throughout your body -- into and out of your cells. Proteins are also a vital component of your immune response.

Types of Protein

Amino acids exist in 20 varieties. Eleven of these amino acids are nonessential, which means they are synthesized in your body. The remaining nine amino acids are essential, which means your body cannot make them, so you must consume them through your diet. Proteins are categorized based on their amino acid structure.

Proteins that contain all of the essential amino acids, as well as some nonessential amino acids, are called complete proteins. Examples of complete proteins include red meat, poultry, fish, eggs, cheese and milk. Proteins that are missing one or more of the essential amino acids are classified as incomplete proteins. Examples of incomplete proteins include rice, beans and nuts. In general, complete proteins are considered nutritionally superior to incomplete proteins.

Considerations

Not all proteins are nutritionally equivalent. Some proteins, such as red meat, whole milk and full-fat cheese, contain a high amount of saturated fat. Other proteins, such as skinless chicken, egg whites, skim milk and low-fat cheese, are low in saturated fat. These proteins, which are referred to as lean proteins, should provide most of your protein intake. Consuming too many high-fat proteins can increase your risk of heart disease.

Protein Recommendations

The Food and Nutrition Board recommends that 10 to 35 percent of your daily calories come from protein. Each gram of protein contains 4 calories; if you are on a 2,000-calorie diet, you should consume 50 to 175 g of protein per day. A more precise way to calculate your protein needs is by your body weight. You should consume 0.4 g of protein per pound of body weight. If you weigh 160 pounds, you need approximately 64 g of protein per day. According to the Centers for Disease Control and Prevention, most American adults consume more than enough protein to meet their needs.