What defines a complete protein?

A complete protein is defined as one that contains all nine essential amino acids that our bodies cannot synthesize on their own and must obtain from the diet. These essential amino acids are vital for various bodily functions, including muscle repair, enzyme production, and hormone regulation.

This definition is crucial in understanding protein sources, as complete proteins are typically found in animal products such as meat, eggs, and dairy, but can also be found in certain plant-based sources like quinoa and soy. The significance of having all nine essential amino acids is that they together provide a balance that is necessary for optimal health.

The other choices do not accurately define a complete protein. For example, being low in calories, found only in animal products, or being easy to digest does not necessarily relate to the completeness of a protein concerning essential amino acids. Therefore, the focus on the presence of all essential amino acids is what truly characterizes a complete protein.