A ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that forces the body to burn fats rather than carbohydrates, for energy requirements. Normally, the carbohydrates contained in food are converted into glucose, which is then transported around the body as energy. However, if there is very little carbohydrate in a diet, the liver converts fat into fatty acids and ketone bodies. The ketone bodies replace glucose as an energy source. An elevated level of ketone bodies in the blood, a state known as ketosis. (1)
In Keto Clarity, the authors define Ketosis as “a metabolic state that happens when you consume a very low-carb, moderate-protein, high-fat diet that causes your body to switch from using glucose as its primary source of fuel to running on ketones. Ketones themselves are produced when the body burns fat, and they’re primarily used as an alternative fuel source when glucose isn’t available. In other words, your body changes from a sugar-burner to a fat-burner. Depending on your current diet and lifestyle choices, becoming keto-adapted can take as little as a few days and or as much as several weeks or even months. So “being in ketosis” just means that you are burning fat.” (2)
(1) Ketogenic diet, from Wikipedia.
(2) Moore, J., Westman, E. MD (2014). Keto Clarity: Your Definitive Guide to the Benefits of a Low-Carb, High-Fat Diet. Victory Belt Publishing at page 32.