What is the Ketogenic Diet? From Seizures to Endurance Sports

The Venn diagram of endurance sports and epilepsy currently has a rather small middle section, but there is something that has been connecting epilepsy and athleticism for years: the ketogenic diet.  In the 1920s, it was discovered that the low-carb, high-fat diet helped to control seizures in children with epilepsy. The introduction of anti-epileptic drugs (AEDs) soon pushed the diet out of favour, but it has stepped back into the limelight in recent years. And whilst its common advocates are people with epilepsy looking for alternative treatments, ultra-athletes and elite soldiers have also been opting for the diet to fuel their challenging lives. We thought we’d take a closer look at how this improbable diet works, and how it made the jump from medicine to an endurance phenomenon.

In the early part of the twentieth century, doctors began experimenting with fasting as a cure for epilepsy (an idea that had in fact been suggested in the medical texts of Ancient Greece). Whilst results were variable, and starving patients was obviously not sustainable long-term, there were noticeable reductions in seizures for some patients. This prompted more research into diet-based seizure-control, and by the 1920s, researchers had pinpointed the ketone bodies, or ketones, created by the liver when a person is starved. It was soon found that reducing the carbohydrate intake dramatically, sourcing the calories from fat instead, would have the same effect on a more sustainable basis, and the ketogenic diet was coined.

avocado for keto diet fat intake

"Starving patients was obviously not sustainable long-term, but there were noticeable reductions in seizures for some patients. This prompted more research"

In a normal, balanced diet, the carbohydrates consumed are converted into glucose, which is then used to fuel the body and for brain-function. By reducing the amount of carbohydrate available, the ketogenic diet mimics starvation, forcing the body to burn fats instead and prompting the liver to create the ketone bodies. These pass into the brain and replace glucose as an energy source, and when there are high levels of ketones in the blood (a state known as ketosis) patients are likely to see a reduction in seizures.

The diet is currently an approved medical treatment for epilepsy, but is often confined to use for children who do not respond to AEDs. There is still no certainty as to why the diet works, but trials have shown that 40% of children placed on the diet have less than half the amount of seizures. Some are even able to reduce their medication. Those who do not experience seizure control still show benefits such as increased alertness, awareness and responsiveness. There is a lack of study into the effectiveness of the diet on adults, but interest in using it as a form of treatment, regardless of age, has increased.

In 2017, the ketogenic diet was one of the most-Googled health topics of the year, with more than four times as many searches as previous years, according to Google Trends, and this is in large part due to the diet being searched for as a weight loss solution. On the face of it, the diet seems counter-intuitive as a health concept. In an effort to remain in ketosis, people on the diet will eat vast quantities of stuff usually avoided: full-fat cream, bacon, coconut and olive oils, and bakers’ quantities of eggs and butter. And whilst the concept of reducing processed carbohydrate intake is fairly common for weight-loss, a keto diet will also reject many go-to health staples ‒ fruit and sweet vegetables such as carrots and peas are all off-limits. Because of these extreme restrictions, individuals should be working with a specialist dietitian to find a suitable plan, and when using the diet to control seizures, a neurologist would be involved as well.

"The diet seems counter-intuitive as a health concept... full-fat cream, bacon, coconut and olive oils, and bakers’ quantities of eggs and butter."

a plate of palma ham for ketogenic diet

There are variations with differing levels of strictness that may be used, depending on the person and their seizures. In the Classic Keto, a person would be on a ratio of 4:1 or 3:1 fat content to protein and carb combined, and they will usually measure their food precisely to the gram. The Modified Ketogenic has a bit more flexibility regarding the ratio of fat to the protein and carb intake, with 2:1 or 1:1 being common. This is still measured precisely, with a dietician individualising the levels of each macronutrient (i.e. fat, carbohydrate and protein) for the patient.  

The MCT Oil Diet, meanwhile, is about having more calories coming from medium chain triglycerides (MCTs) such as coconut oil, instead of long chain triglycerides (LCTs) from animal fats, which are more difficult to digest. The body can process MCTs quicker, and utilise them for energy to help the brain. This makes the diet less strict and allows for more carbs and protein.

A square of almond nuts on a dark background

"Last but not least is the Modified Atkins, which was made infamous due to the 1998 book, 'Dr. Atkins Diet Revolution'"

Low Glycemic Index is a treatment that can vary depending on the individual’s response to carbohydrates.  This form of treatment is based on keeping the glucose response low and using the Low Glycemic Index Chart to eat foods that give the smallest spike in glucose levels. Diets similar to this have proved useful for controlling other conditions, such as diabetes.

Last but not least is the Modified Atkins, which was made infamous due to the 1998 book, Dr. Atkins Diet Revolution.  This style is most commonly used for adults because it is easier to follow and doesn’t require measuring food. This is partly why the Atkins diet became big in the Noughties, with low-carb food becoming common for weight-loss rather than any form of seizure control. But Atkins’ book had limited research to back it as a diet for diet’s sake. The lack of continuation for most dieters meant it became a yo-yo binge for many people using it for weight-loss.   

When looked at as a form of medication, the complex biology explains the necessity for strictness in all variants of  the diet. For a chance of seizure control, the sacrifices to stay in ketosis seem worthwhile for many. But how such restraint became a draw for athletes is less clear. One of the staples of athletics has long been that carbohydrates are fuel for sport, particularly when it comes to endurance. Whether it’s thru-hiking hundreds of miles or running a marathon, the idea of ‘carb-loading’ is ingrained in the sport psyche.  And unlike with epilepsy, there are currently no conclusive studies into the effectiveness of the ketogenic diet on athletic performance. (A pilot study on the performance of endurance athletes was completed in New Zealand only last year, but it concluded that the diet was beneficial to wellbeing, but did not increase performance.)   

Whilst evidence of the diet being effective for performance is lacking, the knowledge of how ketones work could explain the appeal to those needing endurance. It is thought the state of ketosis comes from hunter-gatherer days, when periodic fasting was enforced by situation. The benefits of increased efficiency and heightened alertness in times of fast are obvious, and biologically the ability to use ketones as an alternative fuel-source could have been fundamental to the human race. It is therefore feasible that it is useful for other races.

"Biologically, the ability to use ketones as an alternative fuel-source could have been fundamental to the human race. "

Backpacker on mountain in front of sunset - Aneta Ivanova via unsplash

In 2012, ultrarunner Timothy Olsen broke the record at the Western States 100, a trail run in the Sierra Nevada mountains, California, that has been called the ‘toughest footrace in the world’. The fact that he followed a ketogenic diet was noted. As more endurance athletes such as Patrick Sweeney (who has cycled to Everest Base Camp) and Zach Bitter (who set a record time for a 100 mile-long track run) became known for their cheerleading of the diet, the media ran with it and it was soon the latest must-do.  And it’s not just individuals that are utilising the diet. When the Navy SEALs began using a device called a rebreather to help military divers with extra long dives, they discovered that it caused life-threatening oxygen toxicity seizures. Dominic D’Agostino, a PhD with a background in neuroscience, was brought in to help solve the problem, and he turned to the ketogenic diet as a possible solution. Not only did the diver’s seizures stop, but the soldiers also noted increased energy and clearer thinking in general ‒ both of which would be beneficial to the military.

Scuba diver in dark water - Shane Stagner via unsplash

"Nearly a century after its creation, there is still little understanding as to the reason the diet works, for both endurance and epilepsy"

Whilst the physical benefits of the diet are still anecdotal in most instances, the interest from influential groups like the military has been crucial in funding research. Nearly a century after its creation, there is still little understanding as to the reason the diet works, for both endurance and epilepsy. Now, centres of research such the Institute for Human and Machine Cognition (IHMC) are being supported financially by the United States Defense Advanced Research Projects Agency (DARPA), the Army, Navy, and Air Force to explore this more, whilst biohackers in Silicon Valley are likewise interested in the increased capacity of human output. And importantly for those with epilepsy, they are all intent on trying to find an easier way of replicating the benefits of ketosis. November 2017 saw a development, with a ketone-ester drink that claims to be a shortcut ketosis without the diet. Released to the market at the end of last year, it has not yet been proven if it is effective.

For the moment, there is no harm in athletes experimenting with the effectiveness of this on their performance (though at $30 a bottle, the stamina of their wallet may be a wall for many). Time will tell if such offerings end up being beneficial to those the ketogenic diet was created for.

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