A ketogenic or “keto” diet is an eating plan that derives most of its calories from fat and some protein, with extremely low carbohydrate consumption. The goal is to push the body to metabolize fat rather than glucose in order to lose weight. Burning stored body fat—the aim of a keto diet—is called ketosis. First developed in the 1920s to treat pediatric epilepsy, the keto diet is in wide use in American popular culture. Choosing a plan for eating is highly personal and should always be considered in consultation with a healthcare professional.