See this thread, from this post.
From the article posted here I have read that shamans in south america usually instruct people to do or not do some stuff before the experience. Do you think that it is important? Shoutout to theadvancedapesNo sex, no meat, no dairy, no salt, and no other drugs for a week beforehand.
I generally agree with darkdantedevil. I'm not the most seasoned psychonaut, but I've been around the block once or twice. At the very least, if you follow their regime of abstaining from sex, meat, dairy, salt, and drugs, you'll know during your trip that you gave it your all, that you fully committed. I'm not saying that it would be easy to do, and I'm not saying that it physically matters, but the mind reigns supreme over the body, and that tidbit of reassurance ("I followed the shaman's advice verbatim!") can really give you an edge. Especially when you're tripping balls.
I am by no means an expert, but fasting before most drugs does 2 things: 1. Allows the drug to "come on" significantly faster/a bit stronger (alcohol is an everyday example) 2. And, in the throes of a strong drug experience, evacuating your stomach is pretty common. It can be a bit more pleasant if you only have liquids to come up, and nausea generally subsides faster. I can't speak for the salt/dairy/meat ideas. These stipulations sound like they're trying to appeal to their hippie-ish clientele (who might be fans of "cleanses"). Lastly, lots of psychedelics have some cross tolerances, so if you trip on mushrooms or LSD a week before this experience, you might lessen its intensity; so I assume this is why the "no drugs" rule (besides of any unpleasant interactions which might occur). At the very least you are somewhat more prepared for the decent into the fray.