Certified Dietary Manager (CDM) Practice Exam

What is the definition of an incomplete protein?

1. Foods that contain all essential amino acids

2. Foods that lack the amount or type of amino acid needed for growth

3. Foods that are rich in carbohydrates

4. Foods that are concentrated sources of energy

The correct answer is: Foods that lack the amount or type of amino acid needed for growth

An incomplete protein is defined as a protein source that lacks one or more of the essential amino acids necessary for the body's growth and maintenance. Essential amino acids are those that the body cannot synthesize and must be obtained from the diet. These proteins typically come from plant sources, such as legumes, grains, and nuts, which might not provide a sufficient quantity or range of amino acids. In contrast, complete proteins contain all nine essential amino acids in sufficient amounts and are typically found in animal sources like meat, fish, eggs, and dairy. The other answer choices relate to different dietary concepts: complete proteins would fall under the category of foods with all essential amino acids, while options referring to carbohydrate-rich foods and energy sources pertain to macronutrient classifications rather than protein completeness.