Beyond the importance of eating a diet that includes fruits, vegetables, nuts, whole grains and healthful sources of fats and proteins, there’s little known about foods that specifically support a person’s energy level.
That being said, there are certain foods that give more energy under specific circumstances, as well as foods that sap energy.
During exertion, muscles burn carbohydrates first. To keep your energy levels stable, avoid highly refined carbohydrates—white bread, white rice, white potatoes, and white, processed pastas. They’re digested and absorbed almost as fast as refined sugar.
When you eat sugary foods, your blood sugar shoots up and your pancreas floods large amounts of insulin into your bloodstream. You feel amazingly alert and energized—for a short while, because the insulin rapidly lowers your blood sugar and leaves you less energetic than you were before you ate the sweets.
Instead of highly refined carbs, choose complex carbs—high-fiber whole-grain bread, brown rice, whole-grain pasta and most vegetables, foods that take longer to break down and cause blood sugar levels to rise and fall more gradually.
Source: Harvard Medical School Healthbeat, March 14, 2013