Background: I’ve been doing keto for about a month (paleo before that). I feel as though my body is fairly fat adapted. I IF every day, nearly do OMAD but try not to eat too much protein in one sitting due to insulin spike, maybe eat in a 4 hour window. I have absolutely no trouble whatsoever fasting 20 hours a day. I feel fantastic while fasting, tons of energy. I’m a plumber and I have been outperforming all my colleagues physically, skipping lunch, etc, without feeling like I’m pushing myself. I eat <25 net carbs a day, 70g protein and the rest fat (1700 cal - I feel full for a solid day at this caloric intake) . Get tons of dark leafy greens and eat a bunch of Avos and a good variety of meats.
Anyway, this past couple weeks I’ve been experimenting with longer fasting. I did a 33 hour fast, and broke the fast with a typical keto meal (maybe a bit more protein than usual, but vast majority was fat). I cruised right back into eating without any dip in energy levels whatsoever. It was seamless and awesome and if anything improved my performance on the job.
Then, I decided to try a 48 hour fast. That’s a sleep, a full working day, no food in the evening, another working day, then breaking the fast that evening. I felt absolutely incredible during that fast. Tons of energy.
On the last day I started to feel a tiny bit hungry. I knew I could have kept going without much of a problem and it probably would have faded away. But I had fun experimenting and figured I can always try a 3 day fast next week so I decided to break the fast.
I ate another keto meal. Maybe a bit more protein than usual, but negligible carbs.But basically a couple avocados, some bacon, some smoked salmon and steamed veggies with coconut oil…
About 20 minutes after I started experiencing the most absolute horrible feeling. I felt run down, lethargic, cranky. I was feeling great right before I ate. This feeling lasted for a solid two days. I was just so insanely tired. Stuck to keto still. I did some research and found some things about vit b1 and b5, sodium and water. I ate some nutritional yeast and some salt lemon water. I felt better later, but not nearly as good as I felt during the fast/before it…
Id really like to do these fasts again because they feel so good. But I don’t want to experience the refeeding hangover. It sucks, a lot. If I knew what caused it then I would be able to prevent it in the future.
Any advice would be greatly appreciated