High quality protein is best defined as which of the following?

• A. A protein that lacks essential amino acids
• B. A protein that contains all essential amino acids in the pattern needed by growing animals
• C. A protein that contains carbohydrates
• D. A protein from plant sources only

Answer: (B)

High-quality protein means a complete protein that provides all essential amino acids in the amounts and proportions the body needs for growth and tissue maintenance. That’s why the statement about containing all essential amino acids in the pattern needed by growing animals is the best definition. Proteins that lack one or more essential amino acids are incomplete and thus lower in quality. Carbohydrate content isn’t relevant to protein quality, and limiting the definition to plant sources only ignores the fact that complete, high-quality proteins can come from animal sources as well.