This is something that comes up time and time again. And these foods cause concern for many coeliac as it confuses the issue.
Genius bread comes in for a lot of flak and that seems to be because of its high fat content, also some coeliac have problems with xanthan gum and physilium husk. These are gums that replicate gluten and are very hydroscopic so that they absorb a lot of moisture and this is like roughage and physillium husk is used in colonic irrigation, it is a seed grown in Pakistan and used as a thickener there in may foods.
I have problems with fatty foods regardless of whether they are dairy or not so I have to be careful with rich foiods that have a high fat content, I seem OK with Genius bread but don't eat very much very often.
If I make a crumble with a fruit high in fructose and have it with cream then its like a laxative for me which's a shame as I love fruit crumbles with cream.
I have the worst trouble with palm oil and I really like these spreads like mushroom pate but they are like I have had an enaema, which's no fun. Palm oil is used in these pate's and in soap making as it sets firm.
I think that this could help coeliac who are still having trouble with their diet, so if anyone else wants to put what upsets them then please do, it does not mean that these foods are not suitable for all coeliac just that they have been flagged as problematic to some of us.
So here's the foods I have noticable problems with:
Palm oil, Rich foods high in fat, fruit high in fructose,
Millet and oats and I avoid codex wheat and traces of barley malt like in Branston type pickles and even marmite.