Which of the following is NOT considered a complete protein?

A complete protein is one that contains all nine essential amino acids required by the body for various functions, including muscle repair and growth, hormone production, and immune function. Animal-based proteins tend to be complete, whereas many plant-based sources are typically incomplete.

Ground meat, Swiss cheese, and soy milk are all considered complete proteins as they provide all essential amino acids. Ground meat, being animal-based, contains enough of the essential amino acids required for daily dietary needs. Swiss cheese, a dairy product, also represents a complete source of protein due to its amino acid composition. Soy milk is derived from soybeans, which are unique among plant proteins, as they contain all essential amino acids, making them a complete protein source.

On the other hand, pinto beans, while nutrient-rich and a good source of protein, do not provide all the essential amino acids in adequate amounts. They lack certain amino acids that must be obtained from other food sources, classifying them as an incomplete protein. Therefore, while pinto beans are a valuable part of a balanced diet, they do not meet the criteria of a complete protein on their own.