According to the Treatment Outcomes Survey data, multi-day fasting is the most effective treatment. 19% of people who tried it rated it highly versus 4.8% for the next best treatment.
I wouldn’t start with the most extreme forms of fasting first. Start with shorter fasts first like 24 hours.
The r/fasting subreddit has a guide on how to do fasting.
It’s an easy to follow guide on how to get started and what not to do.
I don’t know how reliable the Reddit guide is. So I tried to quick find information on how to do fasting safely by using Google Scholar. Unfortunately, there are a number of studies where the researchers will fast their patients for up to 48 hours. However, they don’t provide detailed information on how they fasted the patients. So I haven’t yet found good information on how to fast.
While there are a bunch of people on Reddit who water fast for 30 days, that seems a little extreme. (It’s also risky even in healthy people.)
Now I don’t exactly have data on how long you should fast beyond 48 hours. 48 hours is better than 24-48 hours. Just look at the table below that you’ve seen from earlier:
More people benefitted from multi-day fasting than 24-48 hours.
There isn’t too much data on going beyond 4 days if your goal is to treat chronic illness. One Long COVID sufferer on the Patient Experiences Survey reported being recovered and being helped the most by an 18 day water only fast.
Nobody recovered from intermittent fasting or one-meal-a-day (OMAD). So it seems that the more extreme versions do a little better.
People don’t seem to report that good of a result from them. See the post below to learn how to pull data on those other forms of fasting (Multiday juice fasting, OMAD / one meal a day).
Juice fasting was rated the worst (the survey question included cleanses in that category).
This treatment has real risk of making your symptoms worse. Multi-day fasting is one of the medium-high risk treatment options. If that happens, simply stop. Fasting seems to make some people worse rather than better. If that’s the case, fasting is not for you. We already know that the top treatments are double-edged swords.
I hope this helps.