Sodium depletion through sweat is the main cause of muscle cramping for endurance athletes. By adding Clif Shot Bloks to your activities, you get electrolytes and carbohydrates in an easy-to-eat solution. The soft, chewable Bloks can be eaten prior to activity to increase blood sugar levels and during to maintain energy. At 33-calories these great-tasting cubes make it easy to customize and track your caloric and electrolyte intake. And, they're easy to eat on the fly thanks to Clif's handy Fastpak.