What is a Ketogenic Diet?
A ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that helps the body produce ketones (ketone bodies) and use them as fuel instead of carbohydrates.
The ketogenic diet was created to treat difficult-to-control (refractory) epilepsy in children, however, it is nowadays often used for the treatment of obesity as well. The original therapeutic diet for pediatric epilepsy provides just enough protein for body growth and repair, and sufficient calories to maintain the correct weight for age and height.
The ketogenic diet forces the body to burn fats rather than carbohydrates. Normally, the carbohydrates contained in food are converted into glucose, which is then transported around the body and is particularly important in fueling brain function. However, if there is very little carbohydrate in the diet, the liver converts fat into fatty acids and ketone bodies – this is how weight loss occurs. The ketone bodies pass into the brain and replace glucose as an energy source.
The classic ketogenic diet contains a 4:1 ratio by weight of fat to combined protein and carbohydrate. This is achieved by excluding high-carbohydrate foods such as starchy fruits and vegetables, bread, pasta, grains and sugar, while increasing the consumption of foods high in fat such as cream and butter.
The simplified ketogenic diet is more forgiving of the fat to protein and carbohydrate ratio; instead, it imposes a rather strict maximum amount of carbohydrates per day, not exceeding 50g but oftentimes significantly lower than that. In its most restrictive version, or during the initial week until the body enters the state of nutritional ketosis, the carbohydrate consumption is reduced to max. 20g per day.
For our purpose, a low-carbohydrate diet is ketogenic if it restricts carbohydrate consumption enough to cause ketosis. In this regard, the induction phase of the Atkins diet is ketogenic. Low-carbohydrate diets (and therefore ketogenic diets) are used to treat or prevent some chronic diseases and conditions including: cardiovascular disease, metabolic syndrome, high blood pressure and diabetes, obesity, epilepsy, chronic fatigue syndrome (see ketosis) and polycystic ovarian syndrome.