Which foods provide complete proteins with all essential amino acids?
Complete proteins are foods that contain all nine essential amino acids in proportions similar to human requirements. Most foods of animal origin are considered complete protein sources, including:
Gelatin is a notable exception among animal-derived proteins, as it lacks the essential amino acid tryptophan.1
While most plant-based foods are considered incomplete proteins because they are low in one or more essential amino acids, soybeans are a plant-based source of complete protein. Individuals following a vegetarian diet can still obtain all essential amino acids by consuming a variety of plant foods that complement each other. For example, combining legumes (such as beans) with grains (such as rice) allows their individual amino acid profiles to supplement one another, providing a complete protein profile over the course of the day.1