A complete protein or whole protein is a food source of protein that contains an adequate proportion of each of the nine essential amino acids necessary in the human diet.

Amino acid profile

People who eat a varied diet generally do not have to consider the completeness of proteins of single foods. Different protein sources that are each incomplete on their own, typically are complete when combined. The following table lists the optimal profile of the nine essential amino acids in the human diet, which comprises complete protein, as recommended by the US Institute of Medicine's Food and Nutrition Board. The foodstuffs listed for comparison show the essential amino acid content per unit of the total protein of the food, 100g of spinach, for example, only contains 2.9g of protein (6% Daily Value), and of that protein 1.36% is tryptophan. (note that the examples have not been corrected for digestibility)

Total adult daily intake

The second column in the following table shows the amino acid requirements of adults as recommended by the World Health Organization calculated for a 62 kg adult. Recommended Daily Intake is based on 2000 kcal per day, which could be appropriate for a 70 kg adult.

Concept

In a plant-based diet there is the perceived issue of amino acid content of various individual foods. A satisfying diet however, will include minimum requirements of all essential amino acids. "In addition to grains, such as corn, rice, or wheat, vegetable protein also occurs in legumes, which include beans and peanuts. Grains tend to be deficient in tryptophan and lysine, whereas legumes lack methionine Thus a meal combining grains and legumes such as the Mexican peasant dish of corn tortillas and refried beans is basically complete in amino acid content."

• Stanley E. Manahan