What is a common example of a complete protein?

A complete protein is defined as a protein that contains all nine essential amino acids in sufficient quantities required by the body. Quinoa and animal-derived foods, such as eggs, are prime examples of complete proteins.

Quinoa, a grain-like crop, is unique among plant foods as it contains all essential amino acids in adequate proportions. This quality makes it an excellent protein source for vegetarians and vegans. Eggs are also considered a gold-standard complete protein source because they provide all the essential amino acids necessary for maintaining and repairing body tissues.

In contrast, options like rice, peas, and bread do not provide all essential amino acids in sufficient amounts. These foods can be important components of a diet but usually need to be combined with other protein sources to create a complete profile. For example, rice is often low in lysine, while bread is typically low in certain essential amino acids when consumed alone. Therefore, the correct choice highlights foods that inherently provide comprehensive protein coverage, supporting various dietary needs.