Incomplete proteins are proteins that do not contain all nine essential amino acids that the body cannot produce on its own. These amino acids are crucial for various bodily functions, including building and repairing tissues. Foods that are typically considered incomplete proteins include most plant-based sources, such as beans, nuts, and grains. To obtain all essential amino acids, individuals consuming incomplete proteins can combine different food sources. For example, pairing rice with beans creates a complete protein profile. This practice is especially important for those following a vegetarian or vegan diet, as they may rely on plant-based foods for their protein intake.