He's been having meat and the few veges/bits of salad he could have, GF/DF bread. I guess the only 'maybe' things we didn't cut out were corn and hard cheese - those are low FODMAP but I guess if he was CMPI, maybe the cheese would be an issue

He literally drank only water for weeks. Without the aid of a dietician, I was sticking to the list of allowed foods and not wavering. There's an enormous list of 'avoid' foods, a tiny list of 'eat' foods and a lot more foods to test, as the diet is still in development.
http://www.med.monash.edu/cecs/gastro/fodmap/low-high.htmlHe also won't eat soups/casseroles/porridge which is almost the entire list of alternatives provided, so that made it really tricky.
He has been eating more volume of food because he's been very hungry (that is a common thing with this diet), but no change in the pain - he can't explain it enough that I understand what it is - at the hospital when I took him in, they went immediately to reflux, gave him a liquid to drink which had mylanta or similar and an anaesthetic. Anaesthetic numbed his mouth but didn't touch the pain in his tummy. Then they thought maybe an ulcer, had a scope look all through his stomach and the top 1/3 of his intestine but nothing showed, no damage from reflux/ulcers. Not even inflammation. There's nothing in all his bloodwork, nothing showed up on the CT scan. So he stopped going to the doc and just got on with life. After another 2-3 months, he went to see his doc who said to try this low FODMAP diet to see if it helped, diagnosing IBS which is the diagnosis of exception.
There isn't any particular food that makes it better or worse that he's been able to detect. He puts up with so much I can only tell he's got the pain when he's so bad he should be in the hospital, yk? He's a soldier on type, not a man-flu kinda guy.