The following information was from a talk given by the Sport Science Officer at Stirling University and really sets out how swimmers need to be fueling their bodies. Pre & post pool snacks should be kept handy and drinking fluids depending on demands of the session. Water or Squash for low level technique and endurance, using fingers on the side of the bottle to gauge how much you drink. High carbohydrate drinks for intense training, sprints, at competitions when you have a lot of back to back events. Also to take a snack approximately every 3hrs to maintain glycogen stores.