Though, Blue Jay's answer is really humorous the answer is actually a tepid yes,.. it gives racehorses energy. Feeding horses cereal is consider extra calories (in addition to other foods, such hay etc..), which is needed to fuel the racehorse. They eat different cereal grains such as oats, corn, and barley. Starch is the main fuel source in cereal grains. Starch is the dietary energy source of choice for glycogen synthesis, because starch digestion results in a direct rise in blood glucose and insulin, two of the most important factors involved in glycogen synthesis. Glycogen is mainly stored in the liver and the muscles and provides the body with a readily available source of energy, especially if blood glucose levels decrease. However, starch in racehorses definitely needs to be rationed/balanced for health reasons.