Which macronutrient yields the highest number of calories per gram?

Fat is the macronutrient that yields the highest number of calories per gram, providing approximately 9 calories per gram, compared to protein and carbohydrates, which each provide about 4 calories per gram. Fiber, while a crucial component of a healthy diet, is primarily classified as a carbohydrate and does not contribute significantly to calorie intake because it is not digested and absorbed in the same way as other carbohydrates.

The higher caloric density of fat explains its role as an energy source in the body, where it is often utilized during prolonged physical activity and energy deficits. Understanding this helps individuals balance their macronutrient intake based on their dietary goals, whether for weight management, muscle gain, or overall health.