A ketogenic diet is a very high fat, moderate protein, very low carb medical diet originally developed to treat rare and difficult cases of epilepsy. Variations on the diet have been promoted for facilitating weight loss, but most are not endorsed by health experts. In recent years, studies focusing on the diet’s effects on cancer found reduced tumor size and delayed tumor growth in laboratory animals in which cancer of the colon, gastrointestinal tract and prostate had been induced.