Ketone bodies are molecules produced by the liver during periods of low carbohydrate intake, such as fasting or prolonged exercise. They serve as an alternative energy source for the body, particularly for the brain, when glucose levels are low. The three main types of ketone bodies are acetoacetate, beta-hydroxybutyrate, and acetone. When the body breaks down fats for energy, it converts fatty acids into ketone bodies. This process, known as ketogenesis, helps maintain energy levels and supports metabolic functions. Ketone bodies can be utilized by various tissues, including the heart and muscles, making them essential during times of energy scarcity.