Apologies. Slightly less flippant long(er) answer:
During a fast longer than 2-3 days, your body is burning ketones instead of sugar. Under these circumstances, your body can tolerate blood glucose levels as low as 20mg/dl. That would put most ppl in a coma under normal circumstances.
Any adverse symptoms you experience are more likely the result of releasing toxins than low blood sugar. That's another reason for doing the 5-stage elimination cycle, so-called.
....not forgetting to set appropriate search parameters. There's plenty there on precisely this topic, including the Doc's responses to questions from me. You'll also find info on the elimination cycle if this is news to you.
Hope that helps a little more than my 1st response.