Ketogenic diet is one of the oldest forms of medical treatment for epilepsy. Most ketogenic diet centres have traditionally specialized in treating children ages 0 to 18 years of age. However, there is growing evidence that shows its usefulness in controlling seizures in adults. In the content below, you will find answers to frequently asked questions about the benefits and challenges of this diet therapy. Please note, the ketogenic diet should never be attempted on your own. It should only be attempted with the support of a trained medical team.

What is ketogenic diet for epilepsy?

Ketogenic diet is one of the oldest forms of medical treatment for epilepsy. It is a high fat, adequate protein, low carbohydrate diet used in difficult to control epilepsy. There are different versions of the ketogenic diet available but the basic principles are the same. Ketogenic diet therapy may be adapted for cultural diversity, allergies and tube feeding. It is a therapy for both children and adults.

This diet is not without its side effects, so it is very important to become well informed when considering ketogenic diet therapy. Do not attempt the ketogenic diet without medical supervision from a properly trained ketogenic diet team, especially if you are taking anti-seizure medications. This ketogenic diet team includes a neurologist, a registered dietitian and nurse and sometimes a nurse practitioner, pharmacist, social worker and other specialists.

Ketogenic diet therapy can be a treatment choice for families from a practical and emotional standpoint. The first few weeks of starting ketogenic diet therapy can be stressful, and it is important that your family has a good support network.

You will need to learn how to prepare meals differently, which takes time and work. There also may be some difficulty adapting to the new meals. However, with creative meal planning and sensitivity to your difficulties, along with support from your ketogenic diet team some of these obstacles can be overcome. In time you will adapt with the significant changes and meal preparation and meal time will become easier. Many families cope well with the challenges and would agree that the hard work is worth it if the diet significantly reduces the seizures.

How does the ketogenic diet control seizures?

Fasting has long been associated with reduced seizure frequency. Ketones are produced during extended periods of fasting. When a fast is broken with foods that contain carbohydrates or protein, seizures return. Of course, fasting is not sustainable.

The ketogenic diet is consistently reduced in carbohydrates, adequate in protein, and high in fat which mimics this fasting state and also produce ketones. Ketones are an indicator of an important metabolic change but alone cannot explain the anti-seizure effect. Researchers are studying additional mechanisms of action to better explain why this diet reduces seizures.

Who can use the ketogenic diet?

If seizures are well controlled with antiseizure medications and the medications are well tolerated, many people would not wish to consider trying a ketogenic diet. However, in cases where seizures are not well controlled with antiseizure medications, or where the medications result in difficult side effects, or in cases where surgery is not an option, a ketogenic diet may be recommended.

Most ketogenic diet centres traditionally have specialized in treating children ages 0 to 18 years of age. In Canada there is a ketogenic diet program in most children’s hospitals in each province.

Can adults with epilepsy try the ketogenic diet?

Yes. There is growing evidence showing its usefulness in controlling seizures in adults with medically refractory epilepsy. While some adults may be started on classic ketogenic diet, others will be trained in the modified ketogenic or atkins diet which allows more freedom in dietary choices, and affords them the ability to still enjoy going out to restaurants while maintaining this diet therapy. With proper training and motivation, adults can successfully remain on this diet and gain good control of their seizures. Despite some of the adult ketogenic diets offering a little more flexibility it is still considered a medical therapy and should be initiated and maintained by your medical team.

Toronto Western Hospital is the first ‘Diet Therapy for Epilepsy Program’ in Canada that accepts transition of our growing ketogenic children and also initiates adults on ketogenic diet therapy.

Can the ketogenic diet be applied to other disorders?

The ketogenic diet is also recommended for certain metabolic disorders, including glucose transporter deficiency and pyruvate dehydrogenase deficiency.

Growing evidence is suggesting that the ketogenic diet can also be applied to other neurological disorders and perhaps in brain tumors.

The diet can be adapted for people with allergies, people using tube-feeding, and for cultural food preferences.

Are there different types of diet therapy for epilepsy?

Yes, this is an evolving area. Classical (traditional) ketogenic diet, MCT oil ketogenic diet, modified Atkins diet, low glycemic index diet, modified ketogenic diet are currently used worldwide. The amount and type of fat, protein, and carbohydrate characterizes the difference between these diet types. Different ketogenic diet centres may use different versions of the ketogenic diet. Many centres offer more than one option. Your ketogenic diet trained medical team will help you determine which type of diet is best suited for you or your child. Each patient should be treated as an individual and every ketogenic diet should be tailored to meet their particular needs.

What type of seizures respond well to the ketogenic diet therapy?

There is no way to predict who will benefit from ketogenic diet therapy. The ketogenic diet has been described to be effective for different types of seizures caused by different types of epilepsy.

How effective is the ketogenic diet in controlling seizures?

The ketogenic diet can be effective in treating individuals with drug resistant epilepsy from infancy to adulthood.

Up to 60% of children who try a supervised ketogenic diet experience 50% or greater reduction in seizure frequency.

In 40-50% of adults who try a supervised ketogenic diet experience a 50% or greater reduction in seizure frequency.

How soon after starting the diet do you see reduction in seizures?

Seizure reduction can occur very soon after the ketogenic diet is initiated or it may take several months. During this time, it is important to remain committed to keeping the diet consistent and work with your keto diet team who will help you fine tune the diet to achieve the best seizure control. Commitment to consistency to the diet recommendations is important to determine effectiveness of the therapy in controlling seizures.

What kind of foods will be included on the ketogenic diet?

There are 3 food groups that are required:

  • Fats such as cream, butter, margarine, oils, mayonnaise, salad dressings, nuts, nut butters, avocado
  • Protein such as poultry, red meat, fish, cheese, eggs, milk, nuts.
  • Carbohydrates such as vegetables and fruits. Small amounts of bread, pasta, rice, potato, juice

In a regular diet we eat primarily carbohydrates and protein with small amount of fat. In a ketogenic diet you will eat more fat, enough protein to grow and/or maintain your muscle stores and reduce the carbohydrates significantly.

More specifically, a regular Canadian diet will provide carbohydrates supply about 55% of calories, and fat supplies about 20-40% of calories. In a ketogenic diet, fat will supply 60-94% of calories and carbohydrates significantly less.

Some versions of the diet allow more liberal amounts of carbohydrates or protein. The amounts of fat, protein and carbohydrate should be fine-tuned for each person. Some people will achieve acceptable seizure control on a more liberal ketogenic diet whereas others will require a diet that is more restrictive.

Is the ketogenic diet nutritionally complete?

No. The diet is low in some vitamins and minerals. Your registered dietitian and/or team will recommend particular low carbohdyrate vitamin and mineral supplements that you will be required to take routinely.

How can I begin the ketogenic diet?

Your ketogenic diet team will need to assess the type of diet you will have the best chance of success. Your team will teach you how to prepare the diet. You will receive extensive education about how to follow the diet and how to monitor the diet.

Under trained medical supervision, the ketogenic diet will be initiated by adjusting the regular diet and replacing with the higher fat, adequate protein, lower carbohydrate diet.

The ketogenic diet can be initiated from your home (outpatient) or in the hospital (inpatient). Institutions will differ in how to begin the ketogenic diet.

The initiation can also differ in how quickly the ketogenic diet is phased in and adjusted.

How are meals prepared while on the ketogenic diet?

Consistency of meal preparation and consumption is necessary to see optimal effective seizure control. You should receive training on the proper principles of ketogenic meal preparation. Depending on the type of ketogenic diet, your medical team may require that you weigh foods on a scale, or you will be advised to use household measuring utensils.

Your registered dietitian will calculate and provide you menus. You may also be taught how to plan menus yourself based on the diet prescription determined by your ketogenic registered dietitian. It is important to discuss food preferences and meal ideas with your team to support acceptability of this new lifestyle.

For those who are fed by tube, the registered dietitian will provide you with instructions for preparing and providing the ketogenic formula.

Your medical team can recommend cookbooks and websites that have recipes that can help to make the diet easier to adhere to. Although starchy food like pancakes, muffins, crackers and breads are eliminated or consumed in only small amounts on ketogenic diets, it is possible to make delicious ketogenic versions of these foods using things like nut flours and ground flax or other seeds.

Overall- there will be a need to learn how to prepare meals differently, which takes time and work. There also may be some difficult adapting to the new meals. However with creative meal planning and sensitivity to your difficulties, some of these obstacles can be overcome. Many families cope with the challenges and would agree that the hard work is worth it if the diet achieves seizure freedom or significantly reduces seizures.

Are their tests that are needed before and during the ketogenic diet?

There will be blood tests and other suggested tests that your ketogenic medical team will suggest for you. These tests are needed to determine if it is safe for you to start the diet and also used to monitor tolerance to this treatment.

Will anti-seizure medications be reduced once starting the ketogenic diet?

This is always the hope. When ketogenic diet is well established and seizure control has improved, your ketogenic diet medical team may suggest to begin weaning of a seizure medication.

What are the common side effects of the ketogenic diet?

The most common side effects are constipation that can be supported with some dietary adjustments and laxatives. Other side effects that may occur that are relatively minor and transient include: kidney stones, low sugars, nausea, vomiting, diarrhea, sleepiness. There are some reports of longer term side effects that may include higher cholesterol, reduced bone health, kidney stones, slower linear growth velocity and abnormal heart rhythm.

There are rare side effects that the medical team will test for, including; increased susceptibility to infections, abnormal heart rhythm and, in children, altered growth patterns.

How long would someone stay on the ketogenic diet?

This will need to be discussed with your medical team. Routine monitoring tests will be requested by your team while you are on the ketogenic diet. The results of these tests will also help guide how long this therapy should be required.

If I am interested in trying the ketogenic diet, what should I do?

The ketogenic diet should never be attempted on your own. It should only be attempted with the support of a trained medical team.

If you are interested in trying this treatment option, ask for a referral to a neurologist that works within a centre that offers ketogenic diet treatment. Please see a list of Canadian ketogenic diet programs in Canada below.

Discuss this treatment option with your neurologist. If your neurologist feels that the ketogenic diet is a possible option, then bloodwork tests and other investigations may be required to determine if the ketogenic diet can be safely implemented. You may then meet members of the ketogenic diet team such as a registered dietitian, nurse, nurse practitioner, social worker, child life specialist and pharmacist who may offer their assessment on how best to plan for the ketogenic diet. Please note that many centres may have a waiting list.

Establishing regular meal and snack times while reducing candies, chocolates and sweets is the best way to prepare for starting the ketogenic diet. As well makings sure that the potential ketogenic diet candidate is capable of consistently consuming enough to maintain hydration.

Another way to prepare is to review some of the recommended resources listed below.

Recommended Resources



Ketogenic Diets: Treatments for Epilepsy and Other Disorders. 5th Edition (2011) Authors: Eric Kossoff, John M Freeman, Zahava Turner, James E.Rubenstein

The Keto Cookbook: Innovative Delicious Meals for Staying on The Ketogenic Diet (2011). Authors: Dawn Martenz

The Modified Keto Cookbook: Quick, Convenient Great-Tasting Recipes for Follow a Low Ratio Ketogenic Diet (2015). Authors: Dawn Martenz, Beth Zupec-Kania.


Baranano, K.W. & Hartman, A.L. (2008). The Ketogenic Diet: Uses in epilepsy and other neurologic illnesses. Curr Treat Options Neurol. 10(6): 410:419.

Caraballo, R.H. et al. (2014). Ketogenic diet in pediatric patiens with refractory focal status epilepticus. Epilepsy Res 108(10): 1912-1916.

Cross J.H. & Neal E.G. (2008). The ketogenic diet – update on recent clinical trials. 49 (Suppl.8) 6-10.

Henderson C.B et al (2006). Efficacy of the ketogenic diet as a treatment option for Epilepsy: Meta Analysis. J Child Neurol (21) 193-198.

Kossoff E.H. et al (2018). Optimal clinical management of children receiving dietary therapies for epilepsy: Updated recommendations of the International Ketogenic Diet Study Group. Epilepsia Open.

Kossoff E.H. et al (2009). Optimal clinical management of children receiving the ketogenic diet: Recommendations of the International Ketogenic Diet Study Group. Epilepsia. 50(2): 304-317.

Kossoff E.H. et al (2013) A decade of the modified Atkins Diet (2003-2013): Results, insights and future directions.Epilepsy Behav. 29 (3): 437-442.

Lee P.R. & Kossoff E.H. (2011). Dietary treatments for epilepsy: Management guidelines for the general practitioner. Epilepsy and Behavior (21) 115-121.

Neal E.G. et al (2008). The ketogenic diet for the treatment of childhood epilepsy: a randomized controlled trial. Lancet Neurol 2008: 7: 500-506.

Kossoff E.H. & Rho J.M. (2009). Ketogenic Diets: Evidence for Short and Long Term Efficacy. Neurotherapeutics. 6: 406-414.

Wibisono, C et al. (2015). Ten-year single-center experience of the ketogenic diet: factors influencing efficacy, tolerability and compliance. J. Pediatr. 166 (4): 1030-1036.

Prepared by:

Jennifer Fabe BSc.MSc.R.D. President of Matthew’s Friends Canada and Ketogenic Registered Dietitian at McMaster Children’s Hospital

Christine Williams-Dyjur BSc.R.D. Ketogenic Registered Dietitian, Alberta Children’s Hospital and Medical Advisory Board Member to Matthew’s Friends Canada

Dr. Eduard Bercovici MSc, MD, FRCP(C ). Epileptologist. Adult Epilepsy Diet Clinic, Toronto Western Hospital, University Health Network Nicole Turner BASc. MPH. R.D. Ketogenic Registered Dietitian at McMaster Children’s Hospital. Volunteer of Matthew’s Friends Canada

Last Updated: May 2018