The Ketogenic Diet

Now, I don’t know about you, but only eating one large apple or one cup of rice as my daily carbohydrate intake would give me enough energy to last for two hours, so going ‘keto’ has never been a big draw for me. But setting my personal love for carbohydrates aside, the ketogenic diet has been gaining popularity and everyone is asking about it.

What does going ‘keto’ mean?

Normally, our body will rely on carbohydrates for energy and when they are restricted for a longer period of time, the stores in our muscles and liver run out. This prompts our body to enter a state of ketosis where our liver will turn fat stores and certain amino acids into ketones for our body to use as energy. This isn’t the first pathway that your body chooses to take, but with some effort, your liver can get it done. Seems like a ‘no brainer’ way to make energy because to some extent, everyone will have some extra fat to use. Even elite athletes will have fat stores making this an endless energy source for their performance and ketosis even more appealing.

The backstory?

The ketogenic diet was first invented in the 1920’s as a nutrition treatment for those with epileptic seizures. It was found that the frequency of seizures decreased in individuals that were fasting; and therefore, had a higher level of ketones in their blood. Later, they found that instead of starving yourself, you could follow a low carb, high fat diet and essentially trick your body into entering ketosis to achieve similar results. It has since climbed the social ladder as a weight loss diet (if you’re burning fat, you must be losing fat, right?) and for endurance athletes as an endless supply of energy that could prevent the ‘bonking’ one experiences from the depletion of glycogen stores.

How do you achieve a ketogenic state, you ask?

By eating less than 50 g of carbohydrate a day, which is the about how much are in the examples I started this blog with. A common misconception of the keto diet is that if it is low in carbs, it must be high in protein. But in fact, in order to keep the amount of calories similar for daily energy needs, one must consume around 70-80% of their intake from fat, 20% from protein to spare muscle breakdown, and about 5% from carbs. Keep in mind, that one on a ketogenic diet looks for carbs in all foods, not just your obvious carb-loaded foods. For instance, nuts, seeds, and some starchy vegetables have smaller amounts of carbs that are also taken into account for the 50 g daily max. I won’t lie, this isn’t an easy diet to follow, as it takes some diligence, time, and proper food recording to ensure you stay in ketosis.

A positive aspect of this diet is that ketosis tends to cause a reduction in appetite which can be helpful when you are needing to restrict so many foods (especially if you are around friends who are eating things you can’t!). Overall, if it is done right, the diet will be adequate in most of the nutrients that your body needs to function throughout the day. One of the drawbacks is that because there is a reduction in carbs, this way of eating tends to be a bit low in fibre. This, however, can be supplemented for an additional cost.

So, the big question that all athletes want to know is: Would a ketogenic diet give you a performance advantage?

Current research says: no.

Performance level of those following a ketogenic diet is comparable to those following a regular diet with all the goodness a wide variety of food provides. Over the last two decades, there have been numerous scientific studies conducted on athletes following a ketogenic diet to better understand the impact it may have, but there has been no evidence to show that it will give your performance a ‘leg up’ over the competition. Some conclusions that have come about, is that it can take 2-3 weeks for your body to reach a sufficient level of ketone production that can be used as a primary energy source, meaning that during that time your training could suffer. That also means that you need to give your body some extra time to adapt to this way of producing energy, so it shouldn’t be trialed close to competition. High fat diets can also change your natural metabolism to the point that your body becomes less efficient at being able to return to breaking down carbs properly. Going keto for a long period of time and then trying to go back to using carbs as a primary energy source, could reduce your level of performance.

Research continues to confirm that adequate carbohydrates in your diet is best for your athletic performance (CARBS ARE KING!). Any moderate to high intensity exercise requires carbs to power muscle fibers and carbs are what give you that extra burst of energy to push yourself to the max. On a ketogenic diet, you’re not going to get enough to be able to kick it into top gear. As an athlete, this could disrupt you performing at the level you need to be. So, for all you runners out there, in short, ketosis does not improve endurance performance.

That being said, there is no harm in the average healthy person wanting to try the ketogenic diet to see if they can achieve the results they are looking for. If this is a goal you are aiming for, seek out some guidance from a registered dietitian or sports nutritionist to help you ensure you are getting all the nutrients you need.


  1. Burke, L. and Deakin, V. 2015. Clinical Sports Nutrition. 5th Ed. McGraw Hill Education Ltd. North Ryde, Australia.
  2. Burke, Louise M. 2015. Re-examining high-fat diets for sports performance: did we call the ‘nail in the coffin’ too soon?. Sports Med. DOI: 10.1007/s40279-015-0393-9
  3. Volek, J.S., Noakes, T. and Phinney, S.D. 2014. Rethinking fat as a fuel for endurance exercise. European Journal of Sport Science. DOI: 10.1080/17461391.2014.959564
  4. Tsui, Vincci. 2016. Can Ketogenic/LCHF diets make you a better athlete?.