Which of the following dietary components has the highest energy yield per gram?

The dietary component with the highest energy yield per gram is fat. This is due to the chemical structure of fats, which are composed of long chains of carbon and hydrogen. When metabolized, fat yields approximately 9 calories per gram, making it the most energy-dense macronutrient.

In contrast, carbohydrates and proteins provide about 4 calories per gram. While fiber is a carbohydrate technically, it is not digested in the same way as other carbohydrates, and it therefore contributes little to no energy yield. The unique composition and energy storage capabilities of fats allow them to provide a significantly greater amount of energy compared to other macronutrients, which is crucial for bodily functions and energy requirements, especially during prolonged periods of energy expenditure.