Experience report - A trail marathon in ketosis
Part I - Background
There are lots of discussions out there about people doing endurance exercise on "low carb". I put that in quotes, because usually the advice is to "train low, race high", carb-load on sweet potatoes before the race, and so forth. Mark Sisson's recommendations fall into this category.
But, there are very few reports of people racing on *very* low carb, i.e. in a state of ketosis. So, I thought I'd provide one such report. First, some short background. I got the idea to try this from reading the book Low Carb Performance by Volek and Phinney. It is a really interesting book for anyone interested in this subject. They recommend consuming less than 50g of carbs per day to get into ketosis, and they argue that it's not only possible but beneficial in some ways to train and race in this state indefinitely. The idea is that in ketosis, your liver produces ketones, which can provide up to about 3/4 of the fuel that your brain needs, instead of your brain running on glucose only. This is good not only because is spares glucose, but also because you won't run out of brain fuel and "hit the wall" -- the liver create ketones out of fat, so there is a virtually unlimited supply.
In addition, your muscles adapt dramatically to burning much more fat and much less glucose. This is beneficial for endurance exercise because your stores of glucose are no more than 2000 calories or so, whereas your fat stores are, for practical purposes, unlimited. Some other purported benefits of ketosis are faster recovery, less oxidative stresss and inflammation, being able to go for a long time without eating, with even energy levels and blood glucose, and easy weight maintenance.
The only similar reports I've found are:
Peter Attia's blog
Paul and Cynthia's report on MDA
Some background on me. I'm 34 years old. I have been doing the primal lifestyle for almost two years and love it. Trail running is my sport of choice, but I don't take it too seriously, and don't run a whole lot in training. My exercise for a good week looks something like this:
* bodyweight exercises 1-2x
* rock climbing 1x
* swimming 1x
* hiking 1x
* running 1x
Certainly no "chronic cardio" going on here.
The marathon in question was the Coastal Trail Runs Crystal Springs Trail Marathon. It was to be my first marathon.
Part II - Adaptation
Phinney and Volek explain that it takes several weeks for the body to adapt to the ketosis, what they call keto-adaptation. During this period, there may be some issues like light-headedness, tiredness, etc. This is because the brain is not getting enough energy from glucose, while at the same time your body is not producing enough ketones to fuel it. They also recommend getting a device that measures your blood ketone level, so that you know you're doing it right. I got one of these:
Nova Biomedical - Nova Max Plus
The device itself is cheap, but the ketone test strips are about $2.50 each or more.
My adaptation was surprisingly quick and easy. After one week, my ketones were at 2.5 - the optimal level recommended by Volek and Phinney. I did experience some light-headedness, but this was taken care of by consuming more sodium - lots of sodium. The book recommends 2g extra per day, which is exactly what I did, in the form of bouillon. This completely solved the problem. If I skip one of the two bouillon cubes in a day, the light-headedness returns soon thereafter. In addition, I also put a lot more salt on my food than I used to, so the added sodium is really more than 2g. [EDIT 2012-09-04: I realized that one bouillon cube is two servings, and it's 1g sodium per serving, so I actually took 4g extra sodium per day, in addition to the added salt on food].
While it takes a while to get into the optimal keto-adapted state, it is quite easy to slip out of it. I had a challenge of this sort in the form of a bachelor party camping weekend, with beer tasting at the Sierra Nevada brewery. I moderated my intake of beer and other carbs significantly (which kind of sucked). In the week after, my morning ketone levels were borderline. The book recommends 0.5 or higher. My values were between 0.3 and 0.8, and the race was next Sat. Yikes.
As for the eating on a ketogenic diet, it's awesome. Not only is all the fat quite tasty, but for some reason eating is just much more pleasurable! Each meal is like a feast, even if I'm eating the same stuff I ate before.
My actual running training for the race consisted of exactly two runs. One 2.5h trail run at about a 12min/mi average pace (walked the uphills), and one 3h flat run at similar pace, where I tried to stay under 75% of max HR. Both done with no carbs, of course. The trail run felt a bit sluggish, but it was early in the adaptation period. The flat run was totally fine.
Last edited by elenius; 09-04-2012 at 10:53 AM.
Part III - Race Day
Fortunately, the race is only a 20 min drive from my house. I got up at 6.30, had a breakfast consisting of:
* 1 cup coffee
* 1/4 cup whipped cream with 4 strawberries
* 1 boiled egg
* Sliced cucumber with home-made liver pate that my lovely wife made for me
I also took 4 salt caps (for 1g of sodium) right before the race because I didn't feel like taking any bouillon.
Before leaving my car, I took a blood ketone measurement. However, I didn't look at the result, because I didn't want it to affect me psychologically in case it was borderline like some of my measurements had been in the last week.
I was quite familiar with the course. There are several distances in this race: 5mi, 11mi, 22mi, marathon, and 50k. Last year, I ran the 22mi distance, and won my age group. I was in much better running shape then than I was this time, so I didn't expect anything close to that kind of performance, especially with the added unknown effect of the ketosis thrown in. The marathon course has 3790' of elevation gain, not too bad for a trail marathon in this area, but certainly much slower going than a road marathon! The goal this time was just to finish in 6h or so. And, of course, the plan was to only consume water during the whole race. I had one hand-held 22oz water bottle with me which I re-filled at the aid stations.
The course is very beautiful, mostly under the shade of redwood trees, which came in handy as the temperature got up to 90 degrees! It starts out at the bottom of Huddart Park with a long uphill section. My plan was to walk all the uphills. Consequently, lots of people passed me here. I wore my heart rate monitor, and my heart rate was a disturbingly high 85% of my max HR. Surely this could not be sustainable for the whole race? Maybe it would calm down in the later, flat section? I didn't want to slow down since I was already just walking uphill and people were running past me all the time. I got to the aid station at the top of Huddart Park. I left my shirt there, knowing that I would come back to it on my way back later in the day. It was getting pretty hot.
The next segment goes along Skyline. This 5 mile segment connects Huddart Park with Wunderlich Park, and has some small rolling hills, but very few serious uphills. At this point, I wasn't getting passed anymore. Instead, I started passing a few people. I still felt good when I got to the 2nd aid station, at the top of Wunderlich Park.
In the 22mi race, this is where you turn back and re-trace your previous steps back to Huddart Park. But in the marathon, there is a 4 mile loop you have to do down into Wunderlich park. "Down" being the key, because it also imples "up". It was now getting very hot, and I passed some people who were not handling it very well. I was still able to walk quite fast uphill, and I used about 1/3 of my water to pour over my head, which cools me off better than drinking it. Around this time, I also calculated that I had a good chance at finishing the race in 5h30min rather than my conservative 6h goal, so this now became my new goal.
I got back to the Wunderlich aid station in good shape, refilled water, and headed back along Skyline towards Huddart Park again. It was now getting towards noon, and my stomach started growling. Lunch time. No big deal, I had experienced this before. I've noticed that in ketosis, I still get hungry regularly, but it is a different kind of hunger than non-ketosis-hunger. I can easily just ignore it, and then my stomach calms down. More importantly, my brain doesn't get affected, and I don't feel lethargic or tired if I don't eat. Towards the end of this segment, I was getting a bit lower on energy, and kind of tired of running. I didn't care that I was in a beautiful forest any more - I was completely focused on just moving forward at an even pace. I was still running all the flats and downhills and walking all the (little) uphills.
When I got back to the first aid station, I picked up my shirt, had some water, and looked at my watch. 5h30min would be easy. As I ran out of the aid station, one of the aid people called out "Only 4.6 miles left!". What? I thought I had more like 6 miles left! And what was left was mostly down hill! At this point I realized that I had a good chance at finishing in less than 5h, a whole hour faster than my original estimate. I had no idea how many of the marathon runners were ahead of me or behind me, but I realized there must be more of them behind me than I had thought all along, because I was making pretty good time. Running downhill was a nice change. I got to what I knew was the last stretch along Toyon Road, which is this half paved/half gravel road - the worst part of the race. Everything else is on beautiful single track, and here is this ugly road to taunt you right when you're in your worst shape at the end of your race. Just like in my previous race here, this road seems to go on forever, and I kept looking at my watch, wondering if I was going to make it under 5h. In reality, it is only 1.1 miles. This is still downhill, but I was getting pretty tired now, and I was also running a bit faster to make the time. Finally I got to the finish line in 4:57!
Here's me crossing the finish line.
As soon as I stopped running, I felt awful. But I knew what this was. I just needed to move around a bit and drinks lots of water. I did that, stretched, and had a little bit of water melon and trail mix (not too many carbs!). When the updated results came up, I realized I was in 9th place, and 2nd in my age group! Way better than expected.
Nice finisher medal and age group medal:
In a few minutes I felt fine, not even hungry, and ready to go home. When I got back to my car, I checked the ketone measurement I had taken before the race: 1.7, quite good!
Last edited by elenius; 08-15-2012 at 01:27 PM.
Part IV - Recovery
My heart rate monitor told me that I had burned over 4100 calories during the race. That's over a pound of fat! I realized it would take some serious eating to gain this back. And I did have to get it back. My weight after the race was my lowest in a decade. Also, I had recently checked my body fat % at my wife's work, and it was at 7.3%. Losing a lot more weight at that level is just not a good idea. So, if I had 500 extra calories per day for a week, I would be back to normal. Good thing I like whipped cream.
Normally, after a race, I am tired and hungry and can't stop snacking and eating all day. And I'm not talking about a high-carb diet here, just a reasonable primal diet on perhaps 150g carbs per day. That did not happen this time. I had lots of food and lots of fat, and then I was just calm and not particularly tired. I could also walk without hurting, which seemed unusual after a marathon.
The day after the race, my level or soreness was much less than usual after even a shorter race. I had also noticed earlier that recovery from my other workouts had been quite fast. Impressive. In fact, for the first time ever, I felt like doing a workout the day after a big race. I headed to the pool and swam a mile, which felt great and loosened up the muscles a bit.
Part V - Downsides?
There are various claims about the long term health effects of ketosis.
* The Jaminets (authors of "The Perfect Health Diet") claims that it is hard on your liver, can cause kidney stones, and can compromise your immune system, among other issues:
Zero-Carb Dangers | Perfect Health Diet
* Various sources state that it reduces your T3 (thyroid hormone). That's probably not good.
* The "bulletproof diet" guy claims that it makes his sleep worse
» The Bulletproof Perspective on “Safe Starches” The Bulletproof Executive
A couple of these issues did indeed occur. A couple of days after the race, I got a little bit of a sore throat, which cleared up the next day. Worse, my sleep has not been that good the last couple of weeks, and seemed to get a bit worse after the race. Perhaps this is linked to my inadequate blood ketone levels. The solution would be to eat even fewer carbs. Volek and Phinney explain that everyone's ketogenic carb level is different. It can vary from 20g to 100g or so. My level seems to be quite low. I have been eating probably less than 30g most days. But I will go crazy if I have to count my blueberries...
So, now what? I don't think I will continue this indefinitely. While the steady energy is very nice, I don't think it actually improved my athletic performance (though I do think it improved recovery). The main drawbacks are:
* Having to consume a lot of extra sodium. I am getting really tired of bouillon cubes.
* Having to count carbs and be extremely strict at all times. No 80/20 rule here or you're out of ketosis and have to fight hard to get back in.
* Unknown long term health effects.
I might stick with this a little bit longer just to see if I can do a 10k race in ketosis. A 10k is shorter but much higher intensity than a marathon. It normally relies on a very high degree of glucose burning. It would be interesting to see if it can be done adequately on a ketogenic diet.
There is probably a lot more to say. This has been a very educational experience. If you have any questions, ask away
Thanks for a great post! I am currently trying the same thing. I am not measuring my ketones, but I cant imagine not being in ketosis. My energy level is through the roof and my running is going better than ever. I take it a little more serious than you and I probably would classify myself in cronic cardio. Oh well, its better than smoking and drinking myself to death. I am losing weight as well, although I have some to lose. It really is amazing how easy hunger is to deal with. I dont plan on doing this forever. I like apples and dark chocolate too much. All your information is very helpful. Thanks again.
Congrats on the race and thanks for sharing your experience.
I am sticking to train low race high for now. My first race on primal is for september.
Did you experience any side effects like ketone-breath? Or is it true that is no issue if you are really adapted? I hope you don't find the question impolite, but that is something that makes me scared of trying it.
Wow, I find this extremely useful, as I am interested in running a marathon sometime in my life, and realize that carb-loading is probably not the most desireable state to be in for such a long distance. Thanks for sharing!
Really fascinating - since we can't see the linked pics as yet, do you mind sharing your age with us?
I'm working my way up to running longer distances, and started VLC last year but have been less stringent this year. I may just have to check out the Volek-Phinney book!
The hunger thing is kind of miraculous. I feel like I have to stuff myself a bit to not lose weight. One thing that helps put down some extra calories is home made ice cream sweetened with xylitol (got this idea from Attia's blog).
Originally Posted by clint2
On regular primal diet, I tend to very slowly gain a little weight. I might end up doing a month or two of ketosis every year just to "reset" myself, so to speak.
No ketone-breath. I think that (and many other reported problems of low-carb) may have to do with eating too much protein. The ketogenic diet is moderate in protein, and just very high in fat (about 85% of calories from fat). My friend who is also doing this also has no ketone breath.
Originally Posted by MissPiggy
Yeah, then again, it's probably ok if you just want to do it once or twice. What you really want to avoid is chronic cardio with chronic carb-eating.
Originally Posted by sakura_girl
I'm 34, it says in one of the posts above. The Volek-Phinney book is mandatory reading It's pretty much the *only* source of information for this type of thing, other than random posts on the internet like mine.
Originally Posted by Finnegans Wake
I forgot to say that my HR stayed at an average of 85% of max throughout the whole race. It may be partly because of the heat, and partly just lack of training. Still, I didn't know it was possible to have such a high HR for 5 hours...
I think I also forgot to say that the race was only 3 weeks into keto adaptation. Phinney found that people still improve up to six weeks (and maybe longer) in one of his studies.
Edit: You can find my official race result on the race web site above. My last name is the same as my screen name here.
Last edited by elenius; 08-15-2012 at 04:12 PM.