Which of the following nutrients provides the most calories per gram?

Fats are the nutrient that provides the most calories per gram, yielding approximately 9 calories per gram consumed. This high caloric density makes fats a significant source of energy in the diet. In comparison, carbohydrates and proteins offer about 4 calories per gram. Vitamins, on the other hand, do not provide calories since they are micronutrients that support various biochemical functions in the body without supplying energy. Understanding the caloric values of these macronutrients is essential for meal planning and nutritional assessment, as it helps in managing energy intake effectively. Fats play critical roles beyond energy provision; they are vital for the absorption of fat-soluble vitamins (A, D, E, and K), insulation of body organs, and serving as building blocks for cell membranes. Therefore, recognizing the higher caloric content of fats is essential for both overall nutrition and energy management.