What differentiates complete proteins from other types of proteins?

Complete proteins are distinguished by their ability to provide all nine essential amino acids that the body cannot synthesize on its own. These essential amino acids must be obtained through the diet. Sources of complete proteins are typically animal-based foods such as meat, fish, dairy, and eggs, but there are some plant sources, like quinoa and soy, that also contain all essential amino acids.

The presence of all essential amino acids is crucial for various bodily functions, including muscle repair, immune function, and overall health maintenance. In contrast, incomplete proteins, which are primarily found in plant sources, may lack one or more of these essential amino acids. Therefore, when constructing a diet, it's important to ensure that one gets an adequate amount of all essential amino acids, either through complete protein sources or a combination of different incomplete proteins.

This understanding underscores why the ability to provide all essential amino acids is the key differentiator for complete proteins compared to other types of proteins.