I’m on my first extended fast with a goal of 48 hours. I’m on hour 47 and I feel really good and want to keep going for another 24 hours. I’m Type 2 and was on Metformin, but I stopped a couple days before my fast.
My blood sugars have dropped to between 58-60 in the evenings which is scaring me a little. I would like to exercise, but I don’t want to pass out. Is it ok to go for a walk or should I break my fast?
Any advice is appreciated. Thanks!
Hi Nickie,
Not an expert so what I say with a grain of salt… Hehe.
I’ve done 3 fasts in 3 weeks of abt 48 hours. I’m also on oral meds for my T2D (no insulin) and I also saw low blood glucose numbers as low as yours. I had started the fasts ON meds but stopped them when my BG numbers dropped to 60.
I never had issues with dizziness, lower than 58 BG or anything else. I just kept going and felt fine thru the duration.
Thank u. I guess I will keep on and if I feeel any dizziness I will stop immediately.
Low BG is quite often seen when on keto and fasting. It’s not a thing to worry about if not accompanied by any hypo symptoms. Your liver will make as much glucose as needed by gluconeogenesis. Since your brain is now on 80%ketones, a lower BG is not necessarily an issue
Caveat: I’m not a doctor
It is commonly believed that the brain must have some glucose for certain of its cells, but in a recent lecture, Benjamin Bikman stated that he’s been unable to find any scientific evidence to confirm this.
Dr. Phinney often recounts the story of a study performed by friends of his, on the effects of starvation ketosis. One day, they infused insulin into the participants and drove their blood sugar down to levels of glucose normally associated with coma and death. They were perfectly fine. (Naturally, treating human subjects like this today would be a serious violation of ethical rules.) As Dr. Phinney says, “The only people feeling lightheaded and having palpitations were the ones in the white coats.”
I’m sure there is a glucose level that really is too low, even for people who are fat-adapted—after all, our red blood cells can’t survive without glucose, and there may be other cells in the body, too—but the dangers normally associated with hypoglycemia appear to occur, if they occur at all, at a significantly lower level of serum glucose.
Thank you both.
I signed up for IDM and watched one of Megan Ramos’ videos on blood sugar while fasting and she said that those who are fat adapted typically see 50s and 60s so I feel much better about that. I didn’t feel any differently and wouldn’t have known unless I checked it so I think I just freaked myself out.