Certified Dietary Manager (CDM) Practice Exam

What type of proteins are incomplete proteins?

1. Proteins that provide all essential amino acids

2. Proteins that need to be consumed with other foods to provide essential amino acids

3. Proteins only found in animal sources

4. Proteins that contain excessive amounts of calories

The correct answer is: Proteins that need to be consumed with other foods to provide essential amino acids

Incomplete proteins are those that do not contain all nine essential amino acids that the body cannot synthesize on its own. Instead, they often provide some, but not all, of these essential amino acids. The correct answer indicates that incomplete proteins must be consumed in combination with other foods to ensure that all essential amino acids are obtained adequately. For example, many plant-based proteins, such as beans and grains, lack one or more essential amino acids individually. However, when combined, such as rice and beans, they can complement each other to provide a complete amino acid profile. The other options do not accurately define incomplete proteins. Proteins that provide all essential amino acids describe complete proteins, which are generally found in animal sources and some plant sources, not incomplete ones. Additionally, the notion that incomplete proteins are only found in animal sources is misleading, as many plant proteins fall into this category. Finally, the idea that incomplete proteins contain excessive amounts of calories is irrelevant to defining their completeness in terms of amino acid content.