Ketones are small molecules your liver makes from fats. They have featured in popular diets recently, but they first drew attention in the 1920s when clinicians found that some children with epilepsy recovered on the zero-sugar ketogenic diet, but nobody knew why. "The brain ordinarily loves to work on sugar," said Joseph LaManna, Professor of Physiology and Biophysics at the Case Western Reserve School of Medicine. "But if ketones are available, the brain uses those first." LaManna was studying