Often, a period of fine-tuning is needed before it's clear whether or not a child is going to respond to the ketogenic diet. Doctors often ask parents to try the diet for at least one month, and even as long as two or three, if it's not working at first.
A child on the diet usually continues taking anti-seizure medicine, but may be able to take less of it later on. If a child does very well, the doctor may slowly taper the medication with the goal of discontinuing it altogether.
About a third of children who try the ketogenic diet become seizure free, or almost seizure free. Another third improve but still have some seizures. The rest either do not respond at all or find it too hard to continue with the diet, either because of side effects or because they can't tolerate the food.
A side benefit of the diet is that many parents say their children are more alert and make more progress when on the diet, even if seizures continue. If the diet seems to be helping, doctors will usually prescribe it for about two years. Then, they may suggest that parents slowly begin including regular food in the child's diet to see if the seizures can still be controlled, even with a normal diet.
Sometimes a small amount of seizure medication is started again after the diet is stopped. However, some children may be able to stay seizure free without any further treatment. If the seizures return, the doctors may recommend putting the child back on the diet.