The bad news;
dairy products you should be able to tolerate after a few months but in my case only in moderation.(1/3rd of a yoghurt). Also depends on origin milk..Southern Europe ok.
In france and South Africa I’ve been offered chicken as the vegetarian option so gluten free you can forget.
Rather than using corn flour for thickening a lot of cooks use wheat so often no sauce à la poivre.
Frozen foods especially chips are often coated in wheat flour which stops them sticking and browns them.
No sausages from the British Isles, nor queen of puddings, tiramisu, croissants, bread, héros from NYC, Nan breads, fresh pasta except from Lidl if you can find it..forget about gluten free oats and porridge, Pringles..
and as I was told by the Army Air corps base commander « never trust a f#rt »