Absolutely not. The body is amazing at creating its own metabolic water, but I am doubtful it would be able to keep up with the amount of sweat one produces in a sauna. Dry fasting is also already a powerful stressor - stacking sauna on top of it seems dangerous and excessive.
I’d like to hear from folks that have tried (I thought I remember the Snake Diet guy talking about it). I have a sauna at home and have done an hour after after 18 hrs dry fasted. Not much, I know, but I sweated the same and felt like I always did.
I haven’t done it but some people do it. Cole of youtube channel Snakediet has said he does it and it’s quicker weight loss.
If I were to do it, I would do it at the start, like within 3 hours after my last meal since I’ll be most hydrated at that point and normally no one gets damaged in a sauna if they’ve eaten and drank recently and aren’t ill. Then if I feel worst than I should be for a fast, I would stopn .
If you do it after day 1, then your body might not be holding onto any stored water and therefore can’t produce enough water to replace what you’re sweating out from the sauna and bad things might happen during the sauna itself. I could see a slighter hotter room than normal working, since there are probably times when our ancestors have walked in heat without access to water for a few days. But they would not be in saunas when they haven’t had water in a while.
At the beginning of the fast (if you’re hydrated), it can be a quicker way to dehydrate the body. But I wouldn’t and haven’t done it after the first day, personally. It can be a way to turn a dry fast deadly. And let’s put it this way: you are always dehydrating your body with a dry fast, which is a natural stress. Why would you want to add even more extreme stress? “Death fasting” as some people call it is more of a quick lose weight ideal, but that weight comes back, just like a sauna gets rid of water in your body. But dry fasting is a very healing experience, and I think it’s important to honor your body’s natural way of moving through it, especially if you want to successfully make it to a week