Keto and CrossFit: A Match Made in Heaven?

We’ve heard them all…Zone, Paleo, Atkins, Vegan, Whole 30, and the list goes on and on. The dreaded word: diet. We try these new, stricter methods of eating because we reach a point where we’re unhappy with our weight or physical appearance, our fitness level starts to suffer, or it’s the new fad and all your friends are trying it. New diets are emerging all the time, and one of the most recent to burst on the health and wellness scene is the ketogenic (or keto) diet.

    The basic ideas behind this diet, however, have actually been around for over one hundred years. The main concepts of the ketogenic diet originated back in the 1920s when Dr. Russell Wilder experimented with fat to carb to protein ratios in an attempt to find a cure for epilepsy. What he found was, if the body was kept in a constant state of fasting – which occurs when the body is restricted from creating sugar for energy – then the number of seizures a patient had was reduced. In the years following this discovery, the keto diet had all but disappeared from the more mainstream diet craze until recently, where it has re-emerged and been rebranded as a way to lose fat quickly.

    So, what is the keto diet? In a nutshell, it is a low carb, high fat, and moderate protein diet where energy is derived from the burning of fat and protein rather than carbs (also known as a fasted state). A goal, per se, of this diet is to enter a state of ketosis, which occurs when your body starts burning fat for fuel. A generalized macronutrient breakdown for the keto diet in percentages is as follows:

  • 70-80% of calories from fats
  • 20-25% of calories from protein
  • 5-10% of calories from carbohydrates

Keep in mind that this is just a general breakdown and does not necessarily mean that you need to follow these exact percentages. There are many different versions of the keto diet, some with higher protein and/or carbohydrate percentages, which may be a better fit for your needs.

    One of the most commonly asked questions by the fitness community, especially high-intensity exercisers, is whether this low-carb, high-fat diet will be sustainable given the commonly held belief that carbs serve as a better source of energy. However, according to a six-week study conducted at James Madison University on the effects of a low-carb diet on a CrossFit program, the results showed that the group who ate a strict keto diet lost more body fat and body mass then the group who ate a traditional athletes’ diet. And in regards to performance, both groups made improvements on different exercises such as pull-ups, squats, sit-ups, etc. In another study conducted through Auburn University, the researchers studied twelve participants who were divided into two groups: the ketogenic diet group and the group instructed to continue with their normal training schedule (the control group). The study lasted for twelve weeks and what the researchers found was almost identical to the results of the James Madison University study: fat mass for participants in the keto diet group decreased more than that of the control group and participants in both groups saw the same improvement in performance. It is evident from both of these studies, that the ketogenic diet does not have a negative impact on high-intensity training. In fact, it can actually improve performance because of the tendency for individuals on this kind of diet to lose body fat and mass.

    Before deciding whether the ketogenic diet is right for you, there is one final piece of information you need to know about, and this might be the most important: the “keto flu”. This is typically a two to four week period where individuals on the keto diet experience the most negative side effects. This period takes place because your body is in a state of transition as it tries to get used to using fat as an energy source instead of glycogen. Some adverse side effects that can result are fatigue, weakness, lightheadedness, headaches, muscle fatigue, and nausea. When individuals hear talk about the negative effects of the keto diet on CrossFitters, the “keto flu” is most likely what is being discussed. It is important to understand that these effects are only short-term, but are a very likely outcome if you decide to make the switch to the keto diet.

    So, what should you do? Keep in mind that each individual is different and therefore your body may react differently to this diet than someone else’s. It is also important to note that there are several different types of keto diets and one may fit your needs better than another. Therefore, if you are serious about trying the keto diet for yourself, it may be best to experiment with the different percentage ratios/types of keto diets to find which one your body responds to the best. Lastly, be patient! It will take some time for your body to react to the changes you are making so don’t be discouraged if you don’t see any immediate results. Good luck!