Which macronutrient provides the most calories per gram?

Fats provide the most calories per gram compared to other macronutrients, containing approximately 9 calories per gram. This higher caloric density comes from fats being more energy-rich than carbohydrates and proteins, both of which provide about 4 calories per gram. The structure of fats allows for a greater amount of energy to be stored in a single molecule, making them the most concentrated source of energy among the macronutrients.

Carbohydrates serve as a quick source of energy and are important for various bodily functions, but they do not surpass the caloric content of fats. Proteins are crucial for building and repairing tissues and supporting metabolic processes, yet they also provide fewer calories than fats. Vitamins, on the other hand, are micronutrients and do not provide calories at all. Thus, fats are recognized as the most calorically dense macronutrient, underscoring their role in energy storage and overall nutrition.