What distinguishes complete proteins from incomplete proteins?

Complete proteins are distinguished by their ability to provide all essential amino acids that the body cannot synthesize on its own. Essential amino acids must be obtained through the diet, and foods that contain all nine of them in sufficient quantities are classified as complete proteins. These amino acids play critical roles in various bodily functions, including tissue repair, growth, and overall metabolic processes.

While it's true that many animal sources, such as meat, dairy, and eggs, are complete proteins, some plant-based sources like quinoa and soy also provide the full complement of essential amino acids. This means that the assumption that complete proteins are only found in animal sources is not accurate. Additionally, the cost of proteins can vary widely based on numerous factors like source, quality, and market demand, so it cannot be used as a definitive characteristic to distinguish between protein types.

In summary, the hallmark of complete proteins is their comprehensive amino acid profile, which is vital for optimal health and functioning.