This is likely just a function of fluctuating glucose levels. Fasting + becoming fat-adapted can help with this. That said, I have gone through fasts and said

This is likely just a function of fluctuating glucose levels. Fasting + becoming fat-adapted can help with this. That said, I have gone through fasts and said f-it at hour-mark 34 because I was on a deadline. It's not a religion, so do what works for you - but I would at least try it.