Coffee: Research shows that the caffeine in one cup of coffee can temporarily increase metabolism by 15 percent, says Bedwell. And most people will have two to three cups. Whole grains: High-fiber foods take your body longer to digest, which helps speed up metabolism due to the thermic effect of food. Whole grains like brown rice, oats, quinoa, and barley are very high in fiber. Cruciferous vegetables: Broccoli, cauliflower, and Brussels sprouts are especially high in fiber.