A ketogenic diet is a very low carbohydrate diet. It was used many years ago to control diabetes and epilepsy before drugs were discovered. You burn fat on a keto diet.
Keto involves eating less than 20g of carbohydrates per day which is just 5% of overall calorie intake. I do not recommend it long-term but it can be used for a week or two. Clients report that it dramatically reduces sugar cravings which makes it easier to lose weight. There is no wiggle room on this plan for example, 10 jelly beans have 20 carbs!!!
Plan your day and week ahead using the Menu Macro Planner – Low Carb High Fat