Ketogenic diet for epilepsy

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Ketogenic diet for epilepsy

Treatment Overview

When the body burns (metabolizes) fat, it creates substances called ketones. The ketogenic diet tries to force the body to use more fat for energy instead of sugar (glucose) by increasing fat and restricting carbohydrates. It is not yet clear how or why the ketogenic diet prevents or reduces seizures, but it has been shown to be effective in reducing epileptic seizures in some children.2

One version of the ketogenic diet provides 4 grams of fat for every 1 gram of protein and carbohydrate together. People on a ketogenic diet have to eat mostly fatty foods, such as butter, cream, and peanut butter. Foods such as bread, pasta, fruits, and vegetables have to be severely limited. And the person's total calories and fluids are also restricted. At every meal, the food has to be measured carefully so that the right amounts of each food are given. Even a slight departure from the diet can cancel its effect.

What To Expect After Treatment

A person usually has to fast the day and night before starting the diet. The diet is gradually introduced over several days, so that the body can get used to the dramatic change. The person may feel tired and lack energy during the first few days.

Children are usually admitted to a hospital or epilepsy centre when starting the diet so that they can be monitored. The ketogenic diet should always be given under the supervision of a doctor and a dietitian.

Why It Is Done

The ketogenic diet may sometimes be used to treat children who have severe seizures and who have not responded to antiepileptic medicines. It has worked especially well in treating seizures related to Lennox-Gastaut syndrome. It may be a good choice for a child when other treatments have failed to control seizures.

How Well It Works

Doctors are not sure why the ketogenic diet helps prevent seizures. But the diet has prevented epileptic seizures in many children who did not respond to treatment with antiepileptic medicines, including children with Lennox-Gastaut syndrome. Another benefit of the ketogenic diet for some children is that it may reduce or end the need for medicine and thus avoid the side effects that result from medicine.

A review of the results from many studies of the ketogenic diet found that 4 out of 10 children on the ketogenic diet have one-half the number of seizures they had before being on the diet.2 Some children have an even greater reduction.

In one study, children on the ketogenic diet had about one-fourth as many seizures as kids who weren’t on the diet. So a child who wasn’t on the diet had 4 seizures for every 1 seizure that a child on the diet had.1

No one knows why the ketogenic diet prevents seizures in some children and not in others or why it has been more successful with children than with adults. If you have a child with uncontrolled epilepsy, you may wish to discuss with your child's doctor whether a ketogenic diet might be an option.


The ketogenic diet may cause side effects in some people. These are not usually serious but may include:

  • Dehydration.
  • Constipation.
  • Vomiting.
  • High cholesterol level.
  • Kidney stones.
  • Behaviour changes.
  • Slower growth rates in children.

People on the ketogenic diet may develop vitamin and mineral deficiencies unless they take vitamin and mineral supplements. The diet does not supply adequate amounts of the vitamins and minerals the body needs.

Everyone on the diet needs close supervision by a doctor and a dietitian.

What To Think About

Despite the success of the ketogenic diet in some children, many doctors are sceptical of its use. It may pose other health risks to your child, and it is extremely hard to follow. Until more is known about how the ketogenic diet works and what its effects are, some doctors may not recommend using it. If you are thinking about having your child try the ketogenic diet, keep in mind that it has several drawbacks:

  • For the diet to prevent seizures, your child has to follow it exactly. The amounts and types of foods eaten have to be measured precisely. And preparing meals can take a lot of time.
  • The diet does not work for some children, no matter how closely they follow it.
  • The ketogenic diet is not a healthy eating plan for children or adults.
  • People on the diet usually need to take vitamin and mineral supplements.

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  1. Neal EG, et al. (2008). The ketogenic diet for the treatment of childhood epilepsy: A randomised controlled trial. Lancet Neurology, 7(796): 500–506.
  2. Jarrar RG, Buchhalter JR (2003). Therapeutics in pediatric epilepsy, part 1: The new antiepileptic drugs and the ketogenic diet. Mayo Clinical Procedures, 78(3): 359–370.


By Healthwise Staff
Primary Medical Reviewer Kathleen Romito, MD - Family Medicine
Primary Medical Reviewer Brian D. O'Brien, MD - Internal Medicine
Specialist Medical Reviewer Steven C. Schachter, MD - Neurology
Last Revised January 26, 2010

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