Why do vitamins not provide the body with energy?

Vitamins do not provide the body with energy because they are classified as micronutrients rather than energy-yielding macronutrients. While macronutrients—such as carbohydrates, fats, and proteins—serve as fuel for the body's metabolic activities and tissue building, vitamins function primarily as regulatory compounds.12

Instead of acting as an energy source, vitamins facilitate the complex chemical reactions that sustain life. Many water-soluble vitamins, for instance, act as coenzymes that assist the enzymes responsible for energy transfer and the metabolism of macronutrients. In this capacity, they are essential for enabling the body to utilize the energy stored in food, but they do not contain caloric energy themselves.3124