Well I did it. I completed a full month in ketosis, and I celebrated by going out for Mexican and enjoying a big bowl of chips and guacamole, and it was delicious.

I started this experiment because I feel cognitively normal after long races, and I wondered if this was because I was in a state of fat oxidation (ketosis), or if it was due to increased oxygen or dopamine levels. There is no human research proving the benefits of ketosis for brain injury. The theory is based on rodent models, and any existing human benefit is anecdotal. The keto diet has been used in pediatric epilepsy since the 1920s, and is now used in the treatment of cancer, diabetes, Alzheimers, and more.

Achieving a state of ketosis is done through extreme carbohydrate restriction, and if you missed my last post about the diet, you can read more here. Everyone has a different metabolism, and this determines how restricted carbohydrate intake needs to be to achieve high levels of ketones.  While keeping my carb intake below 30 grams, I could not get my ketones above 1.0 mmol/L to a TBI therapeutic level (1.5-3). Interestingly, a TBI friend of mine started the keto diet after I did, and while restricting her carbs only to 50 grams, her ketones were 2.3-2.5. The dietitian I worked with thought, especially with all my running, that I could also get away with 50 grams of carbs, but what we found was that I needed to restrict to below 20 grams to achieve ketones higher than 1.5 mmol/L.  It was exceptionally frustrating, because 20 grams really limits even the vegetables you can eat!

I’ve taken this experiment seriously, recording every gram of my macronutrients (carbohydrate, protein, fat), checking urine ketone strips, and even using a blood ketone meter. If you are looking for one, I recommend the Keto Mojo meter, as the strips are more reasonably priced than other tests. This is not an easy diet, unless you happen to be like my friend who can “cheat” and eat 2 cups of cherries, and still be at 1.6 the next morning….which I might be a little bitter about.

It takes a minimum of 4 weeks for full adaptation, and it is possible I would have seen more benefits if I had continued for a few months.  However, I made it to my one month commitment and decided to stop, for a few reasons:

1.  Twenty grams of carbs is hard. It would have been so much easier to maintain if my metabolism allowed 50 grams.
2.  This diet is really expensive.
3.  Training for ultramarathons felt horrible. Long endurance work was fine, but any speed or hill work was torture, and I was miserable doing something that has brought me happiness these last 2+ years.
4.  I had a migraine 25 out of the 30 days, and prior to the diet I had been stable at one migraine per week for several months.
5.  I did not notice any cognitive improvement.
6. **** Most importantly, I started this diet to achieve the cognitive improvement I feel after a long race. This past Saturday I finished Quad Rock 25 miler. All week my ketones had been around 1.6. I was curious to see how high they would go, and after six hours and 45 minutes of slogging through the mud eating bacon, cheese, avocado and nuts they were still at 1.6. My ketone level was unchanged from before the race, but cognitively I felt much better. During the drive to Fort Collins I was nauseous and got a headache, but on the drive home I was able to read email and texts without a problem. This leads me to believe that ketones are not responsible for my improved cognition.

My plan at this point is to continue on a “lower” carb diet, but only in the sense that I’m not going to eat oatmeal for breakfast, a sandwich for lunch, and pasta for dinner. I’m working out the details with my dietitian. In general, we all tend to eat way more carbs than we need, and this in itself isn’t healthy. So I will be more cognizant about what I reach for, and I will definitely continue adding more fat to my diet. I’m glad I tried this experiment, and I do wonder if ketosis would be more helpful in the early stages of brain injury.

Black Hills 50 miler is on June 23rd, and in the name of science, I’ll test my ketones for a few days before, and a few days after this race, just to see what happens. In the meantime, today seems like a good day to go out for ice cream…for the fat of course.

*As an aside, several people asked me how much weight I lost on this diet. Not a single pound. Ketosis is no more efficient at weight loss than any other diet requiring restriction of food that isn’t good for you. If you are eating enough calories, you wont lose weight. The KetoDiet is a very popular weight loss diet right now, and it works for people because they stop eating junk, and they keep track of everything they eat. If weight loss is your goal, set whatever keto diet app you are using to that function and it will recommend a lower daily caloric level.