After you eat, digest, and absorb foods containing digestible carbohydrates (starches, glucose, fructose, and so on), your blood glucose (blood sugar) level normally rises. The pancreas responds to this blood sugar increase by releasing insulin. Insulin then transports glucose into your body cells (liver and muscles) where glucose can be stored as glycogen, or be used directly as energy. Not enough insulin to regulate high blood sugar levels can lead to increased diabetes risk, but high insulin levels on a frequent basis could promote fat gain.