Which of the following nutrients has the highest Kcal per gram?

Fat is the nutrient that provides the highest amount of calories per gram, delivering about 9 kilocalories (Kcal) per gram. This higher energy content is due to the structure of fat molecules, which consist of long hydrocarbon chains that contain a higher ratio of hydrogen to oxygen compared to carbohydrates and proteins.

In contrast, carbohydrates and proteins both provide approximately 4 Kcal per gram. Vitamins, while essential for many bodily functions, do not serve as a primary energy source and therefore do not provide significant caloric value. The substantial energy density of fat makes it a critical nutrient for energy storage and supply, especially for activities requiring prolonged energy output. This understanding is key for sports nutrition, as it informs dietary strategies for athletes and active individuals who may require higher energy intake depending on their activity level.