Currently my BMI is around 18.9. I’ve tried to do 20-24 hr fasts before but I find I just can’t fall asleep if I stop eating too early, or I start to feel lightheaded going into the second day. I haven’t tried drinking bone broth, salt water, or anything like that during my fast so maybe that’s the reason?
Can I ask why you want to fast? There are a lot of people who will tell you the bmi means nothing (which may be true if your bmi is 26 and you’re very muscular) but with your bmi I can tell you that you are on the edge of being underweight. Even if your goal is longevity, mental clarity, autophagy etc. (I’m myself on day 5 and will break my fast today and am loving it, so I can relate) - for your general health and quality of life you need to increase your body fat and muscle mass rather than thinking about prolonged fasting atm. (I’m a certified nutritional counselor.)You shouldn’t neglect the fact, that further prolonged fasting attempts will bring down your bmi even more and might short-term hurt your thyroid hormones status (nothing you can’t undo necessarily, but still).