What is the ketogenic diet?


Some might consider the ketogenic diet to be a fad diet, however, it was discovered centuries ago for the dietary management of refractory epilepsy.

The ketogenic diet is a high fat, adequate protein and low carbohydrate diet.  

The diet was discovered by the observation of decreased seizure frequency during episodes of fasting.  In 1921, Dr. Wilder at Mayo clinic suggested the ketogenic diet for the long-term management of epilepsy. In terms of this suggestion, it was stated that the benefits of fasting could be recreated through the implementation of a ketogenic diet.

Additionally, the high fat low carb diets could be sustained for a much longer period as it compensates for the clear disadvantages associated with a prolonged period of fasting.

The use of the diet was restricted to very young children and strictly impaired individuals as it was considered a last resort therapy, due to its severe dietary restrictions, unpalatability and limited access to ketogenic diet centers.

Nevertheless, currently, the ketogenic diet is a well-established non-pharmacological treatment for childhood refractory epilepsy.

The ketogenic diet in refractory epilepsy:


Today, there are established ketogenic diet clinics worldwide with dietitians trained and experienced in administering it.  The John Hopkins Hospital in Maryland (US) is an example of such a clinic, with a Child and Adult Epilepsy Diet Centre.

But the question remains: when should someone be referred to such a clinic or dietitian, to initiate the ketogenic diet?  It is recommended to implement the ketogenic diet after two trials of anti-seizure medication has failed to alleviate the frequency and/or the severity of seizures .

Initial anti-seizure drug (as standalone therapy) control seizures in approximately half of patients with newly diagnosed epilepsy .  

The remaining half of the patients, normally those suffering from drug-resistant/refractory/intractable epilepsy, may benefit from the ketogenic diet.

Systematic reviews of ketogenic diet therapies in children with refractory epilepsy suggest that 33-56% of children achieve ≥50% seizure reduction and approximately 16% achieve seizure freedom . 

Clinical reports suggest that ketogenic diets are less effective for adults with epilepsy not related to brain injuries. This is seen all the more in women, suggesting the hormonal milieu may be part of the reason why, and possibly hinting as to why some of these patients seem to ‘grow out’ of the ketogenic diet’s initial benefits. Surgically removing parts of the brain (lobectomy) or implanting devices that stimulate the vagal nerve are alternative options for these patients .

Most anti-epileptic drugs (AEDs) act by blocking the calcium channels our cells use to for their most basic functions.

Keep in mind that the ketogenic diet is the treatment of choice for GLUT1 deficiency syndrome and pyruvate dehydrogenase deficiency (PDHD), which are two distinct disorders of brain energy metabolism .

What about adults with epilepsy?


Some ketogenic diet therapies, for example, the classical ketogenic diet, may be too restrictive for adults suffering from refractory epilepsy and for those refusing pharmacological treatment and is associated with decreased compliance.  

However, with the development of less restrictive diets such as the Modified Atkins Diet (MAD), Medium-Chain Triglyceride (MCT) Diet, and the Low Glycaemic Index Treatment (LGIT), the diet is associated with increased compliance in adults .  

Therefore, the ketogenic diet can be used safely in the adult and adolescent population, with a response rate similar to those seen in children .

The ketogenic diet and variants thereof


Traditionally, the long chain triglyceride (LCT) diet was used, but recently, it has appeared that the medium chain triglyceride (MCT) diet is more effective and palatable .

This is primarily as a result of the unique metabolism of MCT oils and the higher ketone yield per gram as MCT oils bypass normal absorptive pathways and as such are metabolized faster .   

The increased ketogenic potential results in the patients having lower dietary fat demands, thereby allowing for a greater intake of protein and carbohydrates which are associated with increased compliance .

The ketogenic diet is characterized by ratios between total fats and the sum of the carbohydrates and proteins. The ratio is calculated based on the total grams of fat to the total grams of protein and carbohydrates combined.

Up until recently, the 4:1 ratio or also known as the classical ketogenic diet (CKD) has been the most commonly used therapeutic ratio.

The modified Atkins or modified ketogenic diet (MAD/MKD) has a ratio of 2:1. These diets are less restrictive, compared to the CKD and are most likely to be used in infants, adolescents, and adults.

The LGIT relates to a ratio of approximately 1:1 compared to the ketogenic diet, with emphasis on the consumption of low glycemic index (GI) foods (GI of <50), as well as a low glycemic load. 

The LGIT is not normally recommended in those suffering from refractory epilepsy, as the diet brings with it a greater intake of carbohydrates, however, the LGIT can be a more manageable option for those wanting to follow a ketogenic diet for weight loss or other less urgent health conditions.

Reason being, the LGIT has more food options since it allows a wider variety of fruit, vegetables and other fibrous plants. Therefore, the LGIT is rarely associated with vitamin or mineral deficiencies as well constipation, nausea or other side effects often associated with poorly-formulated ketogenic diets eschewing whole plant or animal foods.

Implementation of the ketogenic diet


The ketogenic diet used to be implemented after a 24-hour fast, however, studies have illustrated that the state of ketosis is reached more rapidly after a period of fasting, though, fasting is not required to reach a state of ketosis.

If a patient is going to fast prior initiation the diet, it is recommended to initiate the diet within a hospital setting, where the patient can be monitored and has immediate access to medical support.  

The ketogenic diet can also be implemented at home with daily visits to the clinic if it is not initiated with a fast.

There are various companies that produce ketogenic products (such as KetoVOLVE by Nutr-e-volution) in order to increase the compliance of the diet.  Some products are powdered, oils or liquid emulsions.

What changes in medication are required?


Those on a ketogenic diet require strict monitoring by an experienced medical team, this includes, at minimum, a registered dietitian and a neurologist.  The frequency of follow-up sessions remains patient specific.  

It can take up to three months for a ketogenic diet to alleviate seizure frequency and/or severity, the dietitian will alter the diet as required while the neurologist will alter the medications as needed.  

Medication adjustments may include a decrease in dosing of anti-seizure medication as the ketogenic diet may start to alleviate seizures.  (listen to our podcast with Ellen Davis for a deeper discussion on this matter:


Podcast: Episode 10 – Medical uses of ketogenic and low carb diets with Ellen Davis


Take home message


The ketogenic diet and variants thereof has shown promising results in those (from infancy to adulthood) suffering from refractory epilepsy and should be recommended by medical professionals after two trials of anti-seizure medication has proven to be unsuccessful.  

The ketogenic diet should be monitored by an experienced medical professional in order to encourage the benefits and prevent the side effects. The ketogenic diet is both a medical therapy, requiring medical supervision as well as a fine dietary option for healthy individuals.

Written by: Elzette Struwig (RDSA) – http://metabolicamed.co.za/




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