Protein

The primary function of protein-rich foods is to form muscle, bone, and skin and to repair body tissue. Certain proteins also carry hormones and other essential elements throughout your body by way of the bloodstream. Protein-rich foods include meat, poultry, fish, eggs, dried beans, nuts, and dairy products. Grain foods such as breads and cereals are a secondary source of protein.

Proteins are made up of combinations of 21 different chemicals called amino acids. Nine of these chemicals, called essential amino acids, cannot be manufactured by your body and must be obtained from the food you eat. Others, known as nonessential amino acids, are made from the essential type. Proteins from animal sources are called complete proteins because they are rich in essential amino acids. Because proteins in plant foods such as beans or nuts have fewer of the essential amino acids, they are referred to as incomplete proteins. In the past doctors and nutrition experts recommended combining plant proteins such as rice and beans at a given meal to ensure getting enough essential amino acids. But unless you have a protein deficiency, which is rare in the United States, or are a vegetarian, the experts now know that combining proteins is unnecessary as long as your total diet is balanced.

Many men believe that they need to consume an abundance of protein to eat healthfully, but the Recommended Dietary Allowance (RDA) for protein set by the Food and Nutrition Board of the National Research Council is actually quite low. The RDA for protein is 63 grams per day for an adult male, which is about 10 to 15 percent of your total calorie intake. Consuming this amount of protein each day is not difficult. Simply eat 6 to 8 ounces of meat, poultry, or fish and drink a couple of glasses of milk and you have met your RDA. Most Americans eat more protein than that each day--more than they need.