Kylie Keto : Originally started in the 1920s to help treat people with epilepsy, the keto diet is a high-fat, low-carb eating plan that emphasizes weight loss through burning fat. By eating foods high in fat and limiting carbs, your body can safely hit ketosis, a state in which your body uses fat—in the form of ketones—as fuel instead of carbohydrates. Because your body's preferred fuel source is carbs, it will always turn to those first.