Foods known to boost energy levels naturally include complex carbohydrates, such as whole grains, fruits like bananas and apples, and protein sources, including nuts and yogurt. These foods provide a steady release of energy due to their nutrient composition. Additionally, foods rich in iron, like leafy greens and legumes, can help improve oxygen circulation in the body, enhancing energy levels. Staying hydrated is also crucial, as dehydration can lead to fatigue.