Jin,
I think you have to find what works for you. I personally dont like fasting, Ive tried it and I find that its worse on my body.
I like to consume something light.. Usually I consume ayahuasca at night.. So Ill have a good breakfast (fruits, bread and avocado), then a light lunch towards the afternoon (could be for example some steamed vegetables, maybe with a little bit of rice or quinoa), and then maybe 4 hours after my last meal I drink aya.
I find ayahuasca used to tell me a lot about eating habits when I didnt have it balanced, but now its more of a non-issue.. I think a lot of people go really "overboard" on the diet thing, I think its more important to eat well
every day and just eat light the day of aya, than to eat bad/heavy/industrial food every day and then do a one day fasting thing for aya. We already know it has nothing to do with the MAOI diet because harmalas are RIMAs, not irreversible MAOIs and neither affecting MAO-B.. Some will claim spiritual reasons, but since nobody has patent or monopoly over spiritual matters, you have to see for yourself what you think is good or not. I wonder if maybe it didnt have to do with, when indigenous people started having access to manufactured goods, they used it without control, too much refined salts and sugars and all kinds of things, and then ayahuasca was telling them to manner down.. And then it became a 'rule', but maybe the point was to find a balance, not to have a dogma that you follow the day before and after and then the rest of your life you do exactly the same as always.
As for after, I would just follow the same guideline of eating light and healthy, once you come down better imo than just after purging.. Fresh/raw stuff digests good ime.. No need to eat a lot, just a little bit to give the body some energy. Again, thats only my way, you have to find what works for yourself.
Another thing, not to nitpick but, if youre using rue and mimosa, thats not ayahuasca.. Ayahuasca = caapi (or caapi containing brews). In theory rue also has some harmalas but its not the same as caapi, it also has other different plant compounds, and ayahuasca has different ratios of harmalas plus other different alkaloids plus other different plant compounds. In my experience Ive come to preffer caapi to rue but I think you can still learn a lot and have great experiences with rue. Try caapi out one day and see for yourself if you like it.
Endophytyk, I think the no pork taboo in different cultures is because hundreds of years ago, pork was a dirty meat, the pigs would be eating garbage and transmitting diseases, so it became part of religious teachings, but nowadays I think its as "dirty" (or clean..) as any other meat. I think these days some of the mass produced chicken is the dirtiest meat one can find (hormones, antibiotics, bad conditions of growth etc) and yet it isnt focused on in any religion, maybe in 200 years chicken eating will be taboo
