73. Epilepsy and the Ketogenic Diet

In the UK about 1 in 100 people suffer from epilepsy. Therefore there is considerable interest in using diet as a means of controlling the condition. Despite the fact that national policy continues to recommend that people should reduce the intake of fat, especially saturated fat (SFA), there are growing doubts about the reliability of this advice. In fact, there is now convincing evidence that many of the individual saturated fatty acids play an important role in the body’s normal functions. On the other hand, excessive consumption of the carbohydrates, particularly those that are rapidly broken down and absorbed such as sugar, is now acknowledged as one of the prime factors which contributes to the development of many of the common chronic diseases/conditions. These include diabetes, kidney disease, hypertension, obesity, heart disease and cancer.

As a consequence there is growing interest in understanding the potential benefits of a ketogenic diet. Essentially this a diet which compared to the typical one consumed in the UK or the USA has a lower content of carbohydrate and a higher content of fat.

With respect to epilepsy it is highly significant to note that as long ago as the 1920s, ketogenic diets were being used to control the condition with a fair degree of success. Unfortunately it fell out of favour because of the development of many drugs and because the dietary guidelines which were devised in the late 1970s/early 1980s included a very strong recommendation to reduce the consumption of SFA.

However in recent years there has been renewed interest in the use of the ketogenic diet as a treatment for epilepsy. For example a research team from Johns Hopkins Medical Institutions in the USA has reported considerable success (1). Over a 4-year period, 23 children with infantile spasms, aged 5 months to 2 years, were started on the ketogenic diet. After 1 year, almost half of the children had improved by>90%. All of them had improved by >50%. It was reported that 57% had their medications reduced or discontinued by 12 months. It was also found that 57% showed improvement in development, which was correlated with seizure control. Independent factors that predicted improvement included age younger than 1 year and previous exposure to 3 or fewer anticonvulsants. No child has died, although 7 children had diet-related adverse reactions.

A few years later Elizabeth Neal and colleagues conducted a randomized controlled trial (RCT) at the Great Ormond Street Hospital in London (2). 145 children aged between 2 and 16 years who had at least daily seizures (or more than 7 per week), had failed to respond to at least 2 antiepileptic drugs and had not previously been treated with a ketogenic diet agreed to take part in the study. 73 were assigned to the ketogenic diet and 72 acted as the control group. Because of drop-outs, only 103 children completed the study, of which 54 were on the diet and 49 were controls. After 3 months it was found that the frequency of seizures in those on the ketogenic diet had been reduced to 62% while there had been an increase to 137% in the control group. In 5 children in the diet group the seizure reduction was >90%. Some side-effects including constipation and vomiting were reported.

All of these results are really very impressive. For anyone who has epilepsy there is everything to gain and very little disadvantage by trying to make changes to the habitual diet. So the question is:

“What exactly is meant by a ketogenic diet?”.

There are plenty of different ideas about how to answer this question but I suggest the best approach is to understand the basic principles and try to find the most suitable ways of applying them to any particular individual. The basics are:

  1. Keep carbohydrate-containing foods to a minimum. The case against sugar is getting stronger every day. The big problem is that nowadays sugar is present in many different types of processed food. Avoid sugar-sweetened soft drinks like the plague. Many low-fat versions of foods such as yoghurts have been formulated by removing the fat and replacing it with sugar. Bread, potatoes, pasta and rice are all sources of starch which breaks down to the simple sugar glucose. Where possible choose the less refined version so that the glucose is only released slowly. With breakfast cereals, those which are high in sugar will break down very quickly resulting in rapid build-up of blood glucose (bad news) whereas with porridge there is slow release (good news).
  2. Forget the official advice and include plenty of fats/oils in the diet. However it is crucial to appreciate the differences between the different types of fat with respect to health. There is virtually universal agreement that the trans/hydrogenated fats, which are present in some processed foods (eg baked goods) are damaging to health and should be kept to a minimum (3). Fortunately the food industry is taking steps to eliminate them. Nevertheless there are many good reasons for consuming as much food as possible which has been prepared in the home.

We are continually bombarded with marketing messages that the polyunsaturated fats (PUFAs) are good for us because they lower cholesterol. However the rationale which underpins this is fundamentally flawed. The whole cholesterol story has been totally discredited. Details can be found here (4). There are 2 main families of PUFAs, namely the omega-3s and the omega-6s. Going back about 100 years ago the ratio of omega-6: omega-3 was about 1. Ideally it should be no higher than 4 but into a typical diet today it is round about 15-30. The omega-3s are present in foods such as oily fish whereas those which lower cholesterol are primarily omega-6s. So these should be avoided (5).

In fact what we really need are the SFAs (6). This means that we can consume full fat milk and other dairy products as well as the fat that is present in various meats. If possible choose foods which have been prepared from animals which have been fed on grass. A particularly good source of SFAs is coconut oil (7). Of the monounsaturated fats, I prefer olive oil, especially when the food is not being cooked. When heating is involved coconut oil is best because it will not break down.

  1. As a general rule try to include plenty of vegetables in the diet but I do not advise excessive fruit consumption because of the sugar content. Nuts, seeds and berries are now readily available in the supermarkets all make a valuable contribution to a balanced diet.

The trick is to introduce changes gradually and to try various strategies. It is important to find out what is best suited for any individual. From the perspective of an epilepsy sufferer, there is very convincing evidence that changes suggested here will not only reduce the frequency of seizures but should also be beneficial in helping to avoid a range of other diseases.


  1. E H Kossoff et al Pediatrics (2002) 109 (5) pp780-783
  2. E Neal et al (2008) The Lancet Neurology, 7 (6)pp 500-506 doi:10.1016/S1474-4422(08)70092-9
  3. https://vernerwheelock.com/?p=354
  4. https://vernerwheelock.com/?p=270
  5. https://vernerwheelock.com/?p=153
  6. https://vernerwheelock.com/?p=155
  7. https://vernerwheelock.com/?p=301
  8. http://authoritynutrition.com/top-10-evidence-based-health-benefits-of-coconut-oil/


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