How do you know one specific thing worked, and it wasn't something else? Or just mere coincidence? As someone who has Crohn's disease I have lost track of the times someone has said "oh, blah worked for this person" etc etc.... all anecdotes, with no way of deciding whether there are side-effects that need to be weighed-up. No thanks.
At the end of the day, it's just you doing what works for you. When you do find something that works for you, it's just another anecdote that won't work for everyone else, but it's hard to argue with what makes you happier.
Also, it's not like eating less is exotic or risky. It's one of the many things I'd try if I was suffering.
We should be (and there are people who do) encouraging people to learn how their diets, their behaviors affect them emotionally, physiologically and psychologically. Scientific studies really aren't as applicable to the general population as one would like to believe. So the only way to learn is to experiment on themselves.
This is the point, a sample n=1 is only valid for that one person. You can only make educated guesses on what to test on yourself, but probably you need something slightly different from everyone else.
I do not know much about your disease, but for a diet is it pretty harmless to experiment if you are not doing anything extreme and keep yourself informed on current science
Keep a journal.
Try to have an established routine, then try one and only one new thing at a time.
Do a lot of reading to try to develop a mental model to fit it into.
I have absolutely no idea what you mean by this.
If you have never fasted before, you need to read up on fasting. If you want to make dietary changes, you read up on lots of dietary stuff. Etc.
If you have a specific diagnosis, you can read up on the latest research into that, plus related stuff. For example, I read stuff about genetics and the gut biome because that helps me put things into context.
You do a thing and something happens. You note it and try to figure out what the process is. Was it random? Was it coincidence? Was it causative? If so, how? You build from there.