see digestive systemdigestive system, in the animal kingdom, a group of organs functioning in digestion and assimilation of food and elimination of wastes. Virtually all animals have a digestive system. In the vertebrates (phylum Chordata, subphylum Vertebrata) the digestive system is very complex.
For information on ketogenic diets as a lifestyle choice or for weight loss, see Low-carbohydrate diet and No-carbohydrate diet. The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control (refractory) epilepsy in children. The diet forces the body to burn fats rather than carbohydrates.
Fat: Most of the calories in a ketogenic diet come from fat, which is used for energy. The exact amount of fat a person needs to eat will depend on carbohydrate and protein intake, how many calories they use during the day, and whether they are losing weight (using their body fat for energy).