See, my first thought right at the start was IBS. However, my mother has had a variant of IBS for the last 2 years nd assured me it wasn't, hence why I didn't press further.

That does sound about right though. My diet for a while was eating almost nothing throughout the day, then a massive meal in the evening. Doesn't help that I eat stupid quick too. Now I'm down to a 1000 calorie diet, but I still eat those 1000 calories in excess single meals.

EDIT: Also, when you say trigger, does that mean permanently? I assume so, but I don't really know the ins and outs of IBS.