Contrary to what one may think at first, the ketogenic subject is quite broad and to cover it well will require several posts. In the first post I will focus on the description of the ketogenic diet and its application to epilepsy, for which it was initially developed. A second post will be dedicated to its possible modes of action. Understanding how the ketogenic diet works can help optimize the treatments in which it is involved, and help design new therapeutic applications. The use of the ketogenic diet to treat ailments beyond epilepsy will be discussed in a third post. Finally, variations of this diet, which can make it accessible to a wider audience will be detailed in a later post. There are so many unsuspected applications of the ketogenic diet that there might simply be something in there for you… actually, there might be something in there for me, but more on this later.

A diet to treat epilepsy?

The ketogenic diet is a high fat, adequate protein, low carbohydrate diet, which was discovered in the 1920′ to have beneficial effects on patients suffering from epilepsy (1). Actually, the effect that was first described was the “water treatment”, by which children suffering from epilepsy were not given any food – only water – for up to 25 days! In many cases, the starvation stopped the seizures. Unfortunately, the treatment was not sustainable. The ketogenic diet was designed to produce similar effects while providing sustainable nutrition. This treatment was somewhat forgotten in the 70′ and 80′ due to the development of new anticonvulsant drugs, however, it regained popularity in the late 90′ for children and patients with intractable epilepsy (epilepsy that can’t be controlled by the use of medications).
Anticonvulsant medications fail to control seizures in more than 30% of individuals suffering from epilepsy (2). For these patients, the ketogenic diet has become a very valid option.

What is the ketogenic diet?

The classic version of the ketogenic diet relies on the use of three or four times as much fat compared to protein and carbohydrates (the generally recommended amount of fat in a ‘normal’ diet is 10 to 20%) (3). The amount of protein ingested is calculated to be the minimum required. In addition, the total amount of food is kept low in order to force the body to switch from carbohydrates to fats as its main source of energy. Examples of menus following the ketogenic diet can be seen here.

Does it work?

The rates of success of the ketogenic diet vary somewhat in the literature but studies report at least 38% of patients experiencing a decrease of 50% or more in frequency of seizure (4). A collaborative study on 216 children with epilepsy stated that the ketogenic diet allowed more than 20% of the patients to become seizure free, while another 36% achieved a reduction of their seizure frequency of more than 75% (5). This result is quite remarkable when we consider that the diet is generally followed by individuals for whom all other treatments have failed. When individuals stopped the diet, 75% of children remained symptom-free. However, it is also important to note that the number of patients unable to continue the diet long enough to see effects is significant (up to 35% in the previously mentioned study).

Are there side effects?

Although the ketogenic diet does not involve the use of medications to treat epilepsy, it has been associated with possible adverse effects (6). Reported side-effects include nausea, constipation, metabolic acidosis (an acidification of the blood related to uncontrolled fatty acid metabolism), kidney stones, increased cholesterol and poor growth due to hypoproteinemia (level of proteins too low). In the majority of cases, side-effects could be managed by a close monitoring of the patients. Acidosis was reduced by allowing free consumption of fluids. Kidney stones were associated with concomitant use of anticonvulsant drugs. Hypoproteinemia required frequent checking of protein blood levels and adequate nutrition assessments. While it is important to remember that the ketogenic diet, especially in its classic form, is no “natural diet”, some authors insist that the side-effects were of lesser intensity than with anticonvulsant medications. Also, since the introduction of the diet, less restrictive variations have been considered, which still offer interesting benefits, while possibly limiting side-effects. These will be discussed in a later post.

Scientific references mentioned in this article (in order of mention)

1. John M. Freeman, Eric H. Kossoff, Adam L. Hartman,State-of-the-Art Review Article:The Ketogenic Diet: One Decade Later, Pediatrics March 2007; 119:3 535-543; doi:10.1542/peds.2006-2447

The authors present a clear history of the ketogenic diet and describe its use and possible modes of action in the case of epilepsy. The article reports the potential benefits of the diet for other neurological disorders, such as Parkinson disease, Alzheimer’s disease and some types of brain cancer. The potential use of the ketogenic diet for autism, depression and diabetes mellitus is also mentioned.