This fact sheet contains answers to some of the most commonly asked questions about the diet. Further information about the ketogenic diet may be obtained from a video and a book about the diet.
The video is available from The Charlie Foundation, 501 10th Street, Santa Monica, CA 90402. Phone 1-800-FOR-KETO (1-800-367-5386).
The book, The Epilepsy Diet Treatment: An Introduction to the Ketogenic Diet, by Freeman JM, Kelly M, and Freeman JB, may be obtained from Demos Vermande Publishers, 386 Park Avenue South, NY, NY 10016. Phone 1-800-532-8663.
Further information about epilepsy in children may be obtained from: Seizures and Epilepsy: a Guide for Parents by Freeman J, Vining EPG, and Pillas DJ. 2nd ed. 1997 Johns Hopkins University Press. Balt.
What is the ketogenic diet? The ketogenic diet is a high-fat, very low carbohydrate diet used in children who have epilepsy that is difficult-to-control with current medications. The diet should be considered for children who have more than two seizures per week despite treatment with at least two different anticonvulsant medications. The diet is also used when the frequency of seizures, despite medications, interferes with the child’s function, or when the medications themselves cause substantial adverse reactions. This diet is not currently being used in adults.
Who can be helped by the diet, and how much? Many children with epilepsy can be helped by the diet. There is no way to predict whether it will be successful – except to try it. Traditionally the diet has been used in children between 2 and 10 years of age; however, we have used it in children as young as one year, and in teens. Its use in adults has been limited and there is, as yet, no information about its effectiveness in adults. The diet seems to be most effective in children with “drop” type (myoclonic, atonic or tonic-clonic) seizures, or in the Lennox-Gastaut syndrome. When traditional anticonvulsant medications have not been effective, or if they produce unwanted side effects, the ketogenic diet may be an alternative.
How Effective Is the Diet? Studies done over many years suggest that 20-25% of children on the ketogenic diet will have their seizures well controlled. An additional 30-40% of children will have their seizure frequency decreased by 50%. Approximately 25-30% of patients who try the diet will find, after one or two months, that is not sufficiently effective. These return to the use of medications. Some children may be able to decreases or discontinue their medications while on the diet.
How Does the Diet Work? No one is certain how the diet works. Fasting (no eating) produces ketosis, because the body is unable to completely burn fat it is using for energy. The ketones are the by-products of the incompletely burned fat. The ketogenic diet is a high fat, low carbohydrate diet which simulates the biochemical changes of starvation. In the virtual absence of glucose (or other carbohydrate) the body, and more especially the brain, is able to burn these ketone bodies for energy. How the burning of these ketones controls seizures is unknown.
What is the Diet all about? Ketosis is produced by eating foods which are ketogenic (fats) and avoiding foods which are anti-ketogenic (carbohydrates). The dietician will calculate how many calories a child needs for energy and for growth. This amount is about 75% of the usual recommended daily allowance (RDA) for the child’s age. The diet is usually started in a 4:1 ratio (4 parts fat to 1 part protein and carbohydrate) or in a 3:1 ratio. The dietician calculates meal plans. Each meal is precisely calculated to create a ketogenic formula.
The diet is usually started in the hospital and is always done under careful medical supervision. It is usually started by fasting the child for 48 hours and giving limited amounts of water. Throughout the fasting stage it is important to monitor the child carefully to be certain he does not be come too dehydrated, that the blood sugar does not drop too low, and that the medications do not cause the child to become toxic. Most children tolerate this period well. Once the child has large amounts of ketones in the urine, the diet is gradually introduced. The child is discharged on the fifth day, having started the full diet. Throughout the hospitalization the parents are instructed about the diet, including how to weigh and measure the foods and avoid products or medications which contain carbohydrates.
Even small amounts of carbohydrate such as a cookie, several nuts or carbohydrate-containing toothpaste or antibiotics may eliminate the ketosis and nullify the effects of the diet. Fluid intake is also moderately restricted.
Are children getting enough to eat on this diet? The portions of food on the ketogenic diet are small by usual standards, but the diet is calculated to provide everything the child needs to grow and to gain weight very slowly. The diet requires vitamin and mineral supplements.
Doesn’t a high fat diet cause heart disease and strokes? While the effects of the diet on blood cholesterol and other lipids are under investigation, there is currently no evidence that the diet causes early heart disease or strokes.
What are the benefits of the diet? The obvious benefit of the diet is the potential for seizure control. Sometimes, seizures are controlled as soon as the child becomes ketotic, but this effect may sometimes take as much as a month or longer. Another benefit is that frequently the anticonvulsant medications can be reduced gradually or discontinued. This can, in some cases, provide a child seizure control without the side effects of medication.
How restrictive is the diet? The diet is very restrictive, but the restrictions are usually worthwhile if seizures stop or are significantly reduced. Only the foods and quantities calculated into the diet can be consumed. Medications which are not sugar-free must be avoided.
Are there complications with this diet? During the initiation of the diet there may be nausea, vomiting, and even low blood sugars. This is the reason for starting the diet in the hospital. The ketosis decreases the child’s appetite, so even though the portions are small, hunger is not a problem for most children. Occasional children develop kidney stones, but adjustment of the calcium supplements in the diet and increasing the daily fluids usually resolves the problem. Constipation is often a problem. Ketosis increases absorption of some medications; therefore each child should be monitored for toxicity, and medication dosage should be adjusted when necessary. The goal is for the child to be on as little medicine as possible, or medication free.
Are there different types of ketogenic diets? The main variation of the diet is the MCT (medium-chain triglyceride) diet which allows a slightly greater proportion of carbohydrates and protein while maintaining ketosis. While reported to be as effective as the traditional diet, it seems less well tolerated causing nausea, vomiting, cramps and diarrhoea. We often add small amounts of MCT oil to our diet to increase ketosis and to decrease the constipation.
How long must the child remain on the diet? When a child’s seizures are well controlled, we continue the diet for two years. If seizures are controlled we then decrease the diet to a 3:1 ratio and after six months to a 2:1 ratio. If the seizures recur we increases the ratio once again. Seizure control will return. We then continue the diet for another year. Children, whose seizures are improved but not controlled may remain on the diet for many years.
THE DIET SHOULD ONLY BE USED UNDER THE SUPERVISION OF PHYSICIANS WHO ARE FAMILIAR WITH THE DIET, AND UNDER THE DIRECTION OF DIETICIANS WHO HAVE EXPERIENCE WITH THE DIET.
A team approach which includes the child’s parents, is essential to the success of this treatment. Families need extensive training and support throughout the initial phases of the diet. Finding the appropriate mix of calories, ketosis, medications and fat ratio is an art which requires trial and error as well as sophistication. There is not a standard set of menus that will apply to all children, or even to all children of the same weight. Access to the keto team for assistance in the “fine-tuning” of the diet is the most important ingredient in success. Coaching from parents whose children have been on the diet can provide much needed support for anxious parents during the early phases of the diet, and can relieve some of the burden on the hospital staff.
What are the problems you most frequently encounter? The most common problems are: too many calories seen as weight gain in the child. One hundred extra calories per day equals one pound of weight gain per month. Children should lose weight during the fasting and the initial phases of the diet, and regain their initial weight over about one year. Blood in the urine, or gravel in the diaper are signs of kidney stones. The child needs to see the physician and the urine needs analysis. Most commonly this is due to excess calcium excretion. Excess sleepiness is virtually never due to the diet, but will respond to decreasing medication. Continued seizures on the diet may also decrease when medications are decreased.
Can the diet be used in a severely handicapped child? Yes. Children profoundly handicapped with seizures may have the diet given as tube feedings (or gastrostomy feeding) if necessary. A carbohydrate free formula can be used.