The primary source of dietary energy for humans is derived from carbohydrates, proteins, and fats. Among these, carbohydrates are the most significant, as they provide a quick source of glucose, which the body readily utilizes for energy. Foods like grains, fruits, and vegetables are rich in carbohydrates and are essential for maintaining metabolic processes. Proteins also contribute energy but primarily serve as building blocks for tissues. Fats, while offering more energy per gram, are used for longer-term energy storage and essential fatty acid needs. Thus, a balanced intake of these macronutrients is vital for optimal health and energy levels.