Protein requirements would most likely be the highest for which of the following individuals?

Choice A reason: Under normal conditions, carbohydrates (4 kcal/gram) and fats (9 kcal/gram) are the primary energy sources, sparing proteins for tissue repair. Proteins (4 kcal/gram) are used for energy only when carbohydrate and fat stores are depleted, as in starvation, making this the function typically handled by other macronutrients.

Choice B reason: Proteins are essential for immune function, forming antibodies and immune cells like lymphocytes. Unlike carbohydrates or fats, proteins directly support this role, contributing 10-15% of dietary protein to immune responses, making this a primary protein function, not typically handled by other macronutrients.

Choice C reason: Proteins, like albumin, maintain fluid and electrolyte balance by regulating oncotic pressure in blood plasma, preventing edema. This is a unique protein function, as carbohydrates and fats do not directly influence fluid dynamics, making this an incorrect choice for a function handled by other macronutrients.

Choice D reason: Proteins are critical for building and repairing tissues, providing amino acids for muscle, skin, and organ synthesis. This is a primary protein function, requiring 0.8-1.5 grams/kg daily, not typically performed by carbohydrates or fats, which lack amino acids, making this an incorrect choice.

Choice A reason: Yams are starchy vegetables, providing about 2 grams of protein per cup, primarily carbohydrates. They lack essential amino acids, making them incomplete and unsuitable as a primary protein source for meeting the body’s needs for tissue repair and enzyme synthesis.

Choice B reason: Oatmeal offers about 5 grams of protein per cup but is incomplete, deficient in lysine. It requires combination with other foods to provide all essential amino acids, making it less effective than soybeans as a standalone source of complete protein for dietary needs.

Choice C reason: Soybeans are a complete protein, providing all nine essential amino acids, with about 29 grams of protein per cup. They support muscle repair, immune function, and metabolic needs, making them an ideal plant-based complete protein source for vegetarians or general diets.

Choice D reason: Almonds provide about 7 grams of protein per ounce but are incomplete, lacking sufficient lysine. They require complementary foods to meet essential amino acid needs, making them less effective than soybeans as a standalone complete protein source for dietary requirements.