Protein

Protein is the major structural component of soft tissue, organs and muscles. Amino acids, the building blocks of protein, are also needed to produce and maintain cell membranes, hormones, blood cells, body cells, immune factors, and enzymes essential for body processes like the digestion of food. Amino acids can also be a source of energy for the body, providing 4 kilocalories per gram. However carbohydrates are a more efficient, and preferred, energy source.

Food & Beverage Sources

Protein is found in both animal and plant foods. Meat, poultry, fish, eggs, milk and milk-based products are the primary animal sources, while dry beans, legumes, nuts, soy and, to a lesser degree, some whole grains are plant-based protein sources.

Recommended Intake Levels

Protein needs are based on body weight. Most healthy adults require 0.8 grams of protein per kilogram of body weight, or about 3.5 grams for every 10 pounds. A diet that provides 10-15% of your total daily calories as protein will generally meet your body's needs. For an individual who consumes a 2000 calorie diet, this translates to 50 - 75 grams of protein per day. Most Americans consume far more than this each day.

Protein needs increase for endurance athletes and those who maintain a rigorous training schedule -- to about 1.2-1.4 grams of protein per kilogram of body weight.

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