The Ketogenic Diet is a high fat, moderate protein, and low carbohydrate diet.
The body uses either cabohydrates or Fats to fuel itself. It automatically goes for the carbs, but if the only option is to fuel itself with fat, it also reprograms your metabolism to burn the fats stored in your body rather than using the glycogen stored in your muscles.
By minimizing carbs it helps to keep your insulin and blood sugar levels from spiking, which means no highs and crashes, or mood swings. This allows your fat cells to begin releasing fatty acids, which your liver will then breakdown to produce what are called ketones- hence the name Ketosis.
Ketosis is the physiological state that is achieved when your body breaks down ketones for energy rather than the glucose from carbohydrates.