In March of 2018 I conducted a short experiment with going on a hike while fasting, the hike itself is described Here:

In this article I want to clarify what led up to the decision to hike fasted and how I prepared for the experiment.

So, if You been following my stuff for any amount of time, You already know that I’m a proponent of low carb nutrition and fuel my own activities primarily with fat. I noticed a considerable shift in my metabolism after the 30 day hike in nutritional ketosis I did in the summer of 2017, after which I no longer need a few days adaptation when choosing to up the carbs for a day or a few. My thoughts are that the prolonged activity during ketosis restored my bodies natural metabolic flexibility and increased my ability to fuel with free fatty acids directly.

I have felt inclined to try an extended fast for quite some time, just didn’t seem to get to it, and now I thought the time was right and the decision was made on pretty short notice.

Just a couple of days before the start of the hike on Friday, March 23rd 2018, I caught myself falling into a pattern of spontaneous OMAD (one meal a day). I had my usual fat coffee in the morning and just wasn’t hungry more than once a day.

Probably this can be explained by stress levels being a lot lower than back in Stockholm and the abundance of sunlight I enjoy here on the island.

Anyway, I was clearly in fat burning mode when I skipped my fat coffee on Friday morning, leaving dinner at 18:00 (6PM) Thursday as my last meal before going out into the hills 13:30 (1:30PM) Friday.

Totalling just short of 80km (50 miles) I ended the hike on Sunday 16:00 and did only take in water and pink Himalayan salt (contains lots of electrolytes besides the sodium) during this time. Admittedly I consumed a lot of water and added about 0.5 tsp salt to each 1.5l bottle.

Timing proved to be perfect and on Sunday night my body told me to end the fast, dinner at 20:00 (8PM) left me with a 74 hour fasting period, maybe it had felt good to go longer if I had not been hiking. For now and under the circumstances, this was exactly right for me.

Now, I can’t stretch enough the importance of being properly fat and keto adapted if You want to copy the experience. Though it is true that fasting is one of the fastest ways of entering nutritional ketosis, doing that while being this physically active can only be a very unpleasant experience.

So, will I do this again?

Well, on the fasting side – definitely! I felt really good the whole weekend, good energy levels most of the time and really no feelings of fatigue or even serious hunger. The plan for now is to incorporate 24-36 hours fasts on a more or less weekly basis with an extended fast every now and then when it fits into my life situation.

At some point, when life’s slow and rather stress free, I´d like to go for a longer fast, maybe 7-10 days, to really reap the health benefits. For now the natural intermittent fasting I do on an almost daily basis will suffice!

That’s all for now, thanks for checking out the post and I hope you found it valuable.

Please share if you did!

Peace // Claes