Nutritional ketosis is a natural metabolic state in which your body is fueled mainly by fats and ketones, instead of carbohydrates (glucose). Nutritional ketosis happens when carbohydrate consumption goes low enough that a person’s liver can convert adipose tissue and dietary fats into a fatty acid known as ketones, then burn the ketones for energy.
Carbohydrates are an energy source, but they’re not the only one your body can use. When there’s very little carbohydrate in your diet, your body has a natural and readily available option – nutritional ketosis. And what it will use is fat—the fat in the foods you eat as well as your own stored body fat.