The ketogenic diet is one of the oldest treatments for epilepsy. It is intended to maintain the starvation or fasting metabolism over a long period of time. If there is very little carbohydrate in the diet, the liver converts fat into fatty acids and ketone bodies. The ketone bodies pass into the brain and replace glucose as an energy source. An elevated level of ketone bodies in the blood, a state known as ketosis, leads to a reduction in the frequency of epileptic seizures.

The diet must be followed very strictly and requires a significant commitment to work effectively. Children on the diet often will not gain weight or grow much during the time the diet is in use. After that, however, growth is expected and should be carefully monitored.

The diet has been used mostly in children with difficult-to-control, generalized epilepsies — such as those with the Lennox-Gastaut syndrome. Lennox-Gastaut is a generalized epilepsy which is characterized by drop attacks or tonic-clonic attacks (with violent, rhythmic convulsions) and often occurs in children with other neurological conditions such as paralysis and mental retardation. It’s often very resistant to treatment. In this group of individuals, the diet can be as successful as medications. Thus, it is most often recommended for children ages 2 through 10 or 12 years old who have been diagnosed with a generalized type of epilepsy, and who have failed to respond to a variety of drugs. Recent studies have shown that the diet may also be effective in those with partial seizures.

The diet is typically started with a period of fasting lasting until the body produces a moderate to large amount of ketones. This initiation period usually takes place in the hospital, so that the individual can be monitored for potential side effects such as vomiting, low blood sugar, dehydration, and seizures. Medications may also be adjusted during this period to prevent sedation (the tranquilizing effect of medications), another common side effect.

A two-month trial period is suggested for deciding whether the diet is effective. If effective, it is typically continued for two years. During this time, individuals are often able to lessen the amount of medication they take for seizures. Many children seem happier and more alert on the diet, even before medication is significantly lessened.

People on a ketogenic diet should be monitored by a dietician, nurse and doctor — particularly a neurologist — familiar with its use. Specialized epilepsy clinics are available to monitor a person on this diet.