How Does the Ketogenic Diet Work. Ketogenic diet ever popular. A ketogenic diet has become very popular with body builders and/or those wanting to lose weight. This diet allows one to lose fat weight without losing muscle mass, and in fact, while gaining muscle mass in the case of some body builders. A ketogenic diet, also referred to as a ketosis diet or a keto diet, forces the body to burn fat as its primary energy source instead of carbohydrates.