Intermittent fasting, specifically the 16:8 method where you only eat during an eight window each day. I’ve been following this habit every day since early August. It started off just to see if I could do it, to find out what it was like. The decision to give it a go was chiefly prompted by a post that explored scarcity - The Darkness You Choose, The Darkness that Chooses You.
I am cherry picking the parts I was inspired by:
When you choose to fast, you’re conducting an experiment with your own machinery. The metabolic switch flips from glucose to fat, from immediate fuel to stored reserves. Your brain shifts into a different gear — sharper, quieter, less cluttered by the constant background noise of digestive processing. This is voluntary darkness: closing the shutter to make the picture clear…
Short-term voluntary scarcity sharpens focus…
We live now in a world where abundance creates its own problems. Choice overload paralyses us in grocery aisles. The tyranny of infinite options can make us less decisive than scarcity ever did. Sometimes constraints liberate us from the exhausting democracy of having to choose everything, all the time…
Fasting is a chosen darkness — you pull the curtains to concentrate the light that remains.
I was inspired to experiment with fasting. I was curious. You don’t know till you try. It’s one thing to say I think I could do such and such but until you try the statement has no weight.
So I started and found out a few things. The first being was that I could do it. I’ve only been eating between the hours of 1.00 pm and 9.00 pm. A regular concession has been milk in tea and coffee but aside from that I’ve stuck to the fast.
My perception of feeling hungry has changed. Feeling hungry used to be a condition to resolve. Nowadays it’s just a feeling I notice and allow. It does not feel like a big hardship. It’s just a feeling. One that passes with time, often with no more than the next distraction.
Interstitial moments. The space between ending one activity and before starting another. The feeling of being at loose end. I felt a need to fill these spaces. It used to be with smoking. I gave up smoking a while ago. The “smoke break” was replaced by the cupboard/fridge/bread bin/biscuit raid. I needed food no more than I needed to smoke. Very often I was not even hungry. Sometimes I actually felt full up but would graze anyway. The need was not about food. It was simply to not feel the way I was feeling. The discomfort of being at a loose end, of what to do next, a distraction from the feeling that often comes with getting on with the next task, a task I may not be looking forward to or feeling that confident about.
Intermittent fasting is helping me to notice, allow and sit with my feelings. They come and go all of their own accord. I knew this but have seldom allowed it. I allow it more now.
So what about the cycling. I read that intermittent fasting helps enhance pancreatic function and sensitivity to insulin. I’ve also read, and as prickly ox pointed out in their post that after a little while your body adapts and finds energy from stored fats rather than the carbs it has become used to being fed. No doubt there is a more scientific way of putting that.
Most days I do a 50km loop. This is often first thing in the morning hence while still fasting. It’s not felt like a big deal. I tend to ride at the same moderate pace all of the time. I believe this habit has helped my body adapt to finding glycogen in fat rather than a ready supply of carbs or from any glycogen reserves in muscles. Given that fat is always available from somewhere I think this has a consequential impact on increasing endurance. This article backs up the idea and explains it much better than I have.
Every month I do at least one ride of 200km or more. The last few have been while fasting. The first 100k of September and October rides were on an empty stomach. I fared much better than I thought I might. I did not ‘bonk’ and neither was my pace markedly different from normal.
Yesterday I set out on a 400k ride. I planned the first control stop at 80k. I got there before 1.00 pm so just had a black coffee and carried on riding. Other than on long rides I only drink decaf tea and coffee. I felt pretty good on the next section and put that in part down to the caffeine. The next control was at 160k. I still had around 10 - 15k to go when 1.00 pm came round. I kept going and got to the stop at around 1.20 pm. 100 miles done on an empty stomach without suffering. This was a first. There is no doubt in my mind that intermittent fasting has increased my cycling endurance.
I kept going for the rest of the day and into the early hours. Got back home around 4.15 am. I could have managed the last 150km better. I did bonk. Nausea and headache mostly. My pace did not reduce by much though, if at all. Luckily the wind was behind me all along the south coast. Lessons learned and will be applied this coming weekend. I have a 600 planned.