ACE Personal Trainer Practice Exam

Which macronutrient provides 9 calories per gram?

1. Carbohydrates

2. Fats

3. Proteins

4. Vitamins

The correct answer is: Fats

Fats are the macronutrient that provides 9 calories per gram, making them the most calorie-dense of the macronutrients. This higher caloric value is due to the structure of fatty acids, which contain long chains of carbon and hydrogen atoms, and their efficient metabolic conversion to energy in the body. In comparison, carbohydrates and proteins each provide 4 calories per gram. Carbohydrates are the body's primary source of energy, particularly for high-intensity activities, while proteins serve mainly structural and functional roles within the body, such as muscle repair and enzyme function. Vitamins, on the other hand, do not provide calories as they are not a macronutrient; instead, they are essential micronutrients that facilitate various biochemical processes in the body. Thus, fats are distinct in their energy provision, emphasizing their importance in a balanced diet, particularly for sustained energy and supporting overall health.