I have from time to time tried various food combinations - but a few months back tried cutting out coffee grains and alcohol at the same time and felt much better after a week and dropped some weight.
I have over the past week picked this up again and with similar immediate results.
It has left me wondering that supporting good stomach health may be a better way to longer term weight loss and health - on the basis of all the research done over stomach issues relating to these food/drinks.
Many love coffee and depend on it I accept, but when you realise a degree of sensitivity then the downsides just do not seem worth it.
Likewise, I would now say the same for alcohol.
Grains and gluten is well covered here anyway, I would only add rice and oats may also not be as helpful as you think - as not gluten per se but also not helpful possibly either.
If others reached this collusion much earlier than me I can only say well done !