The primary source of energy for the body is glucose. Glucose is a simple sugar that is derived from the carbohydrates in food, including fruits, grains, and vegetables. When consumed, carbohydrates are broken down into glucose, which is then absorbed into the bloodstream. The body uses glucose as a critical energy source for cellular processes, powering everything from basic functions like breathing to intense physical activity. Other sources of energy include fats and proteins, but glucose is preferred because it can be rapidly utilized by cells for immediate energy, making it essential for maintaining overall health and activity levels.