What factor is used to determine protein quality?

The determination of protein quality is primarily based on amino acid composition. Proteins are made up of amino acids, which are the building blocks for muscle, tissues, enzymes, and hormones. The essential amino acids—those that the body cannot synthesize and must be obtained through the diet—play a crucial role in evaluating protein quality.

A protein source that contains all essential amino acids in adequate amounts is considered high-quality, or complete. Examples include animal proteins like meat, eggs, and dairy, which typically provide all essential amino acids in the correct proportions. In contrast, many plant-based proteins may lack one or more essential amino acids, thereby reducing their overall protein quality.

While caloric content, fat content, and sugar content can be important factors in overall nutrition, they do not directly relate to the ability of a protein to support bodily functions and health. Therefore, when assessing protein quality, focusing on amino acid composition is essential.