No longer than 7 days , you’ll probably wanna die at that point.
Dry fasting is basically emulating living in a desert. No food no water, not even touching water, like how you’d be in a desert. Brushing your teeth at max, but no showers, no washing hands stuff like that.
The benefits are just that it’s even more pure than water fasting. Everything you get from water fasting but even more. Because now there’s no new water in your system, so your body really starts going to work on everything in your body it can use to survive.
This is all of what I know, hope it gives you a better idea!
I started off doing rolling 72 hour water (snake juice) fasts, then included a 24 hour dry fast in between them for good measure now and again. Nowadays I dry fast all day and only have snake juice in the evenings between 5-10pm within the 72 hours. I’m not sure why but not drinking during the day at work makes it much easier for me - I’ve done about 10 rounds of 72s back to back and not feeling hungry/thirsty at all this way - very few side effects by now.
I would start small - like one day of dry fasting in the middle of your fasting period and go from there - later on you could set aside 3-5 days or a weekend to try it out for longer while you have minimal physical commitments. I think the longer you continuously have been doing the snake diet (with rolling fasts and refeeds), the easier it would become to transition into adding dry fasts.
I don’t have any solid facts offhand about the benefits, but in my experience it was similar to fasting with snake juice, except everything was ramped up - quicker transition into higher ketone production, very rapid lowering of inflammation, very quick drop in water weight, and after about two 72s with dry fasts in the middle no more sugar cravings.