In human nutrition, complementary proteins are combinations of plant foods that together provide all essential amino acids in adequate amounts. Which of the following pairs is an example of complementary proteins?

• A. Apples and almonds
• B. Rice and beans
• C. Chicken and eggs
• D. Peanut butter and olive oil

Answer: (B)

Verified step by step guidance

1. Understand the concept of complementary proteins: these are combinations of plant-based foods that, when eaten together, provide all the essential amino acids that the body needs but cannot synthesize on its own.
2. Recall that most plant proteins are incomplete, meaning they lack one or more essential amino acids, whereas animal proteins are usually complete.
3. Identify pairs that combine different plant sources to complement each other's amino acid profiles, such as grains (which are low in lysine but high in methionine) and legumes (which are high in lysine but low in methionine).
4. Evaluate the given options: 'Rice and beans' is a classic example of complementary proteins because rice (a grain) and beans (a legume) together provide a complete amino acid profile.
5. Recognize that pairs like 'Apples and almonds' or 'Peanut butter and olive oil' do not form complementary proteins because either one or both do not provide a complete set of essential amino acids, and 'Chicken and eggs' are both animal proteins, so they are not examples of complementary plant proteins.