What is the primary source of energy in the human diet?

Carbohydrates are considered the primary source of energy in the human diet because they are readily broken down by the body into glucose, which is then utilized by cells for energy. Glucose is the preferred source of energy for the brain and muscle cells during periods of high intensity activity.

In contrast, proteins serve several important functions in the body, including building and repairing tissues, but they are not the body's main energy source. While fats do provide a significant amount of energy and are essential for various bodily functions, they are metabolized more slowly than carbohydrates, making them a secondary source when quick energy is needed. Vitamins, while crucial in metabolic processes and supporting overall health, do not provide energy directly. They assist enzymes and other biochemical reactions but do not constitute a source of caloric energy.