What macronutrient accounts for 9 calories per gram?

Fats are known to provide a significant source of energy, yielding 9 calories per gram when metabolized by the body. This high caloric density makes fats an essential macronutrient for energy storage and overall energy balance. Fats play various critical roles, including supporting cell membrane structure, providing insulation, and serving as a reservoir for fat-soluble vitamins. This macronutrient is crucial for athletes who require larger energy supplies, particularly during prolonged or intense physical activities.

In contrast, proteins and carbohydrates provide fewer calories per gram—4 calories for each, while vitamins, which are micronutrients, do not provide calories at all. Understanding these distinctions is vital for athletes and anyone interested in nutrition to optimize their dietary intake for performance and health.