Natural fat, high-fat sauces – Most of the calories on a keto diet should come from fat. You’ll likely get much of it from natural sources like meat, fish, eggs etc. But also use fat in cooking, like butter or coconut fat, and add plenty of olive oil to salads etc. You can also eat delicious high-fat sauces including Bearnaise sauce etc., or garlic butter (recipes).
The ketogenic diet reduces seizure frequency by more than 50% in half of the patients who try it and by more than 90% in a third of patients. Three-quarters of children who respond do so within two weeks, though experts recommend a trial of at least three months before assuming it has been ineffective. Children with refractory epilepsy are more likely to benefit from the ketogenic diet than from trying another anticonvulsant drug. Some evidence indicates that adolescents and adults may also benefit from the diet.
Children who discontinue the diet after achieving seizure freedom have about a 20% risk of seizures returning. The length of time until recurrence is highly variable, but averages two years. This risk of recurrence compares with 10% for resective surgery (where part of the brain is removed) and 30–50% for anticonvulsant therapy. Of those who have a recurrence, just over half can regain freedom from seizures either with anticonvulsants or by returning to the ketogenic diet. Recurrence is more likely if, despite seizure freedom, an electroencephalogram shows epileptiform spikes, which indicate epileptic activity in the brain but are below the level that will cause a seizure. Recurrence is also likely if an MRI scan shows focal abnormalities (for example, as in children with tuberous sclerosis). Such children may remain on the diet longer than average, and children with tuberous sclerosis who achieve seizure freedom could remain on the ketogenic diet indefinitely.
At the core of the classic keto diet is severely restricting intake of all or most foods with sugar and starch (carbohydrates). These foods are broken down into sugar (insulin and glucose) in our blood once we eat them, and if these levels become too high, extra calories are much more easily stored as body fat and results in unwanted weight gain. However, when glucose levels are cut off due to low-carb intake, the body starts to burn fat instead and produces ketones that can be measured in the blood (using urine strips, for example).