Which of the following represents the largest caloric yield among macronutrients?

Fats represent the largest caloric yield among macronutrients because they contain the highest energy density. Each gram of fat provides approximately 9 calories, while carbohydrates and proteins each provide about 4 calories per gram. This higher caloric yield from fats is due to their chemical structure, which allows for more carbon-hydrogen bonds that can be oxidized to release energy.

In contrast, proteins and carbohydrates have a lower caloric yield as they have fewer hydrogen atoms associated with their carbon backbone, resulting in lower energy availability when oxidized. Vitamins, while critical for various biochemical functions, do not provide calories as they are not utilized for energy in the same way as macronutrients. Therefore, when considering the caloric yield, fats clearly offer the highest energy content among the macronutrients.