What is a common source of incomplete proteins?

Incomplete proteins are those that do not contain all nine essential amino acids in sufficient quantities that the body needs. Common sources of incomplete proteins are typically found in plant-based foods. Beans, for instance, are a popular source of plant protein but are known to be low in certain essential amino acids, particularly methionine. This means that while beans provide a good amount of protein, they do not offer a complete amino acid profile on their own.

On the contrary, eggs, meat, and fish are examples of complete protein sources, as they contain all nine essential amino acids in adequate proportions. Therefore, the choice of beans as a source of incomplete proteins is accurate. This understanding is crucial for those looking to create balanced diets, especially for individuals following vegetarian or vegan lifestyles, who may need to combine different protein sources to ensure they are obtaining all essential amino acids.