Let say, if I wanna do 48h extended fast and after breaking that fast, I wanna start another extended 48-72h fast straight away. Is that dangerous? I read from somewhere that we have to take a day off after a prolonged fast so it won’t be stressful to our body..is that true?
48-72h is not what most here would consider a prolonged fast. That would be more like 10+ days. I haven’t come across any research specifically about what you’re asking, but in theory this is what our ancestors did all the time. Eat when they could find food, and go without in between. Fasting is always a stress on the body, and that’s not always a bad thing, but the amount goes up with time fasted. What you propose is kind of an extreme version of intermittent fasting. I don’t think it would be harmful, but it’s not going to be easy either, since the first 2-3 days of a longer fast are usually the hardest.
Above 36 hrs is where you start to need to be very mindful of electrolytes. I’ve done 5-day fasts with nothing but water/black tea/black coffee in the past, but felt much better when supplementing electrolytes. For 48 hrs, then re-feed, then 72 hrs again, if you’re in good health then there’s no problem, in my opinion. Work up to doing them back-to-back, give your body time to adapt. The biggest problems occur when the change is the biggest; going slow and gradual means less risk and more sustainable practice.
What is your motivation to do rolling fasts or 48–72-hour fasts? You have to have a reason for doing it. Otherwise, there are other ways to lose weight. You can do shorter forms of fasting and simply focus on the reduction of calories, which typically occurs naturally with extended fasting. Although I am not sure about the raising or lowering of metabolism through fasting, per se. I do know that if you want to increase your metabolism, lifting weights is a good way to do it.