Not meant to be a carbohydrate replacement. These are just to replenish electrolytes. Not ideal in every circumstance but when used properly, excellent. On a long ski day when I cary plenty of carb calories as solid food, a waterbottle with GU brew is perfect for keeping electrolytes up and preventing cramps. The small canister is good for bringing a couple tabs along on a big push. Give it a bit of time to dissolve.