I decided to do a little experiment with fiber and cycling. Someone on Reddit suggested it might get me further than fast burning sugars.
So, Saturday I ate 800ml of Erwten Soep (dutch pea soup) which was a total of 664 calories, 30.4g fat, 56g carbs, 21.6g fiber, and 37.6g protein. Along with the soup I had a slice of dutch rye bread (it’s very moist, dense and you can throw a pack of this stuff at someone’s head to kill them) which was 100 calories, 1g fat, 17g carbs, 5.5g fiber and 2.5g protein.
So that was a whopping 73g net carbs (fiber subtracted out already) but 27.1g of fiber. I didn’t bolus (take insulin) to cover any of the net carbs because I wanted to go cycling and was hoping maybe the fiber would slow down this insane burn I’ve been experiencing.
Since I can’t exercise on a full stomach, I had to wait about an hour before going out. So I ate, waited an hour and started to get ready. My blood glucose peaked at 7.7 mmol/L when I got up out of my computer desk chair. By the time I had gotten dressed and retrieved my bike, my bg was down to 7.2.
Unfortunately, even with the 73g carbs I ate for lunch and the 27g fiber, I wasn’t able to get much farther beyond my 7km leash (maybe another .25km). However, something interesting did happen. At the 7km mark I was only at 5. Usually at this point I was at 3.8ish. Yes, I could have gone farther but I decided not to push my luck.
Usually I’d have a 150ml box of apple juice or full sugar coke, shove some dextrose or glucose filled candies down and wait for my bg to come back up. I didn’t this time. Being around 5 doesn’t usually give me hypo symptoms so I was feeling OK and I had stuff on me if I needed it. I wanted to see what happened if I just waited. About 40 minutes my bg was back up in the 6’s, all without having to eat anything.
So my muscles love sucking up any readily available glucose and it seems my liver stops pumping it out (or can’t keep up) when I’m actually moving. However, by sitting still and because of the high fiber food that was still absorbing, I was able to naturally bring up my bg without sugar.
Of course this did mean sitting around for 40 minutes in the middle of the wilderness getting eaten by mosquitos. So while interesting, this wasn’t very practical. I also noticed within the next 4km I had to stop again because my bg dropped down into the 4’s… so apparently I reached the end of what could be provided from lunch.
On the second stop on the way back home, my bg stayed around 4.8 and wasn’t coming back up so I did have to pop a dextrose just so I didn’t go too low the last few kilometers home.
Once home, my bg stayed low until I had dinner. Apparently even a high carb, high fiber meal can’t sustain me long enough to get farther than 7km either.
So, that was the great fiber experiment. If nothing else, I did learn something and all that fiber also helped clean me out… so to speak.