see this video on the Treatment Outcomes Survey
and the follow-up Patient Experiences Survey
The first survey strongly indicated that extended fasting was a top treatment. The second survey didn’t indicate that as much. There’s probably an edge to longer fasts, though you should work your way up especially because some people react negatively to fasting.
Dry fasting seems unnecessary (compared to wet fasting), but the data isn’t definitive. I would avoid cleanses and juice fasts, they seem to be worse than wet/water fasting. But again, data isn’t definitive yet.
There’s an old primer on fasting here.