The Ketogenic Diet

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. When the body is in a fasting state, it creates ketones, a by-product of fat-burning metabolism. It has long been recognized that seizures often lessen or disappear during periods of fasting in some individuals with epilepsy.

The diet is very high in fat and low in carbohydrates. When fat is the primary source of calories, ketones are formed. 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.


Your child’s physician will determine if this diet is right for your child. The diet should be used in those who traditional therapies have not worked. The diet requires a strong commitment from the family to measure all fods eaten on a daily basis. No deviation in the diet plan is allowed.
Many children with seizures can be helped by the diet. There is no way to predict beforehand whether it will be successful, you simply have to try it to find out. Traditionally the diet has been used in young children between the age of 1 and 6, with myoclonic, atonic, and tonic-clonic seizures. Recent studies are confirming it’s benefits in children under age 1 and older children although older children may rebel at the food restriction. In every decade since the 1920’s, studies consistently show that 50-75% of children will be helped considerably by the diet.
No one is certain how the diet works. One theory attributes the anti-seizure effect of the diet to the ketones that the ketogenic diet produces. Ketones are the products of fat breakdown. Our body normally burns glucose (sugar) for energy. The body can use these ketones as a source of energy rather than glucose.
Ketosis is produced by eating a balance of foods that provide just the right amount of fat, protein and carbohydrates. A calorie level is determined for each child based on their age and activity level ans about 80-90% of the child’s Recommended Dietary Allowance. To achieve a desired level of ketosis, the diet is calculated in terms of ratios such as 4:1, 3:1, 2:1. In a 4:1 ratio, there is 4 times as much fat as there is protein and carbohydrate combined. The dietitian devises meal plans that complete the required fat, protein and carbohydrate components in each meal. Each meal plan provides the exact number of grams of each food. All food is weighed on a gram scale. The diet is most effective when consumed in it’s entirety. A typical meal includes a small amount of fruit or vegetable, a protein rich food, and a source of fat such as heavy cream, butter or vegetable oil. Ketogenic formulas are available for infants and children with special feeding tubes.
The Diet has never been evaluated in a controlled scientific study. Studies that have followed children on the diet for long periods reveal that 1/3 of children treated with the ketogenic diet have greater than 90% seizure control with half of these children becoming seizure free. An additional 1/3 gain at 50% reduction in seizures. The remaining 1/3 discontinue the diet due to it’s ineffectiveness or it’s difficulty.
The diet is initiated under close medical supervision in the hospital. The diet is initiated gradually and increased to the full amount over a 3 to 4 day period. On the first day, children will drink special ketogenic shakes (eggnog). During this period the dietitian works with the family to explain the diet and answers all questions. The parents prepare all ketogenic meals while learning to measure the foods on a gram scale. During this time blood sugar and ketone levels are monitored. A fasting period is not necessary to start the diet although it is used at some medical centers. During the second and third day, the diet will be advanced to a larger amount of eggnog, ketogenic formula or the ketogenic food.
The diet can become effective immediately or can take several months. Each child is unique and has different seizure patterns and frequency. There is usually improvements within the first 10 weeks on the ketogenic diet.
If the child is on more than one anti-seizure medication, one may be reduced as the child starts the ketogenic diet. The reduction of remaining seizure medication may be made if the child’s seizures improve over time.
The diet alone is inadequate in many vitamins and minerals. Supplements will be prescribed for your child while on the ketogenic diet. The diet is usually used for up to 3 years. A regular diet is then resumed.
The most common adverse effect of the diet is constipation. There are options available to prevent this problem including eating high fiber vegetables that are allowed on the diet and drinking enough water. A less common adverse effect is kidney stones. This problem can be prevented by making sure that the child drinks enough water. Two anti-seizure medications which can cause kidney stones should be avoided with the letogenic diet (Zonegran and Topamax). Other less common adverse effects include elevated lipids and decreased growth rate. Laboratory studies are necessary during the course of the ketogenic diet therapy to ensure that the child is receiving proper nutrition.