Fasting Journal, Day 1 of 4

Why am I fasting? Curiosity, mainly. If you want to know more, here’s the post in which I announced my fasting experiment.

1:30 p.m.

As I understand the science, sometime today or tomorrow my body will switch its energy source from carbs to fat. Glucose, what we normally use for energy, mostly comes from ingested carbohydrates, while ketone bodies, our backup fuel, come from stored fat. There may be a period of glucose “withdrawal” while my body reconfigures to fat-burning mode, but then I should be good to go. Once my body switches to fat-burning mode, other physiological changes will kick in that might be good for me, probably won’t hurt me, and will make me not feel hungry any more.

To help move that process along, I didn’t eat any carbs yesterday and I ate about half the calories I normally do. With fewer carbs in my system before I stopped eating, it should take less time for my body’s glucose stores (glycogen) to drop. When that happens, my body will switch from carb burning (glycolysis) to fat burning (nutritional ketosis). And now I sound like I’m on a hipster diet or something. I blame Tim Ferriss, whose podcast I listened to on the way up to St. John’s. If you want to have the same tenuous understanding of the science as I do, listen to the most recent episode.

So far today, I’ve had four or five cups of coffee, some water, and I’ve taken two short walks. This is the view from my room at the St. John’s Guesthouse, by the way:


It’s impossible not to want to sit next to the window and read. Or gaze. Or go out and walk. Speaking of which, I’ve got a large stack of books calling to me …

3:45 p.m.

I’ve been reading for a while, and my stomach is finally growling. I really want to go upstairs and find a snack. Bad idea, I know. This will pass. I just have to wait it out.

8 p.m.

I expected to feel lethargic after a day of fasting, but I feel fine other than an empty stomach. And the empty stomach isn’t really bothering me. This afternoon, though, I couldn’t stop thinking about food. First I was dreaming about something like bread and pasta. Then I was thinking about meat. When the smells from dinner prep in the kitchen started filling the building, I just wanted to drink some broth. But now I’m feeling okay with not eating.

I feel chilly, but I think it’s just kind of chilly in here. I do have just a little bit of a headache. It’s very mild, but maybe that’s the glucose withdrawal kicking in. My sinuses feel a bit weird. Nothing out of the ordinary with all the leaf mold that’s around, but apparently a weakened immune system is part of glucose withdrawal. I’ll be hiding in my room from anyone who could get me sick.

9:30 p.m.

It’s early, but hey, I’m on my own schedule. I’m turning in.

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