my attacks seem to happen randomly whatever i eat, tried a food exclusion diet but didn't seem to make much difference. 
One thing that does seem to make a difference tho is alcohol, when i have a few bevvies on a night out i pay for it the day after in terms of my gut!
The problem is, i do like having a drink sometimes - i spose everyone has things to keep them sane - particularly if they have to cope with IBS, so that i don't have to worry too much about my stomach on a night out i take a couple of immodiums. It's probably not the best thing to do and i should probably avoid alcohol altogether, but sometimes i think you need to 'stray' every now and then to feel normal.
I'm sure alot of people on this board eat and drink stuff they know they shouldn't every now and then...
But ermm, back on topic! As for chinese or asian food - urban myth has it that in a takeaway fastfood form (the authentic stuff is supposed to taste much different, but i've never been to that part of the world so i wouldn't know) it kind of pioneered the whole putting MSG in food thing to make it taste better. I've heard that MSG isn't good for many with IBS so i guess for alot of people, the type of asian food they may have experienced might not agree with them.
But by the sounds of it, the place you went to sounded quite 'natural' - so it's a bit of mystery as to why you reacted badly to it. Sometimes i think that even eating supposed 'safe' foods doesn't always work. In the past,i've been quite happily going along for a couple of days, coping okay and eating bland food and avoiding stuff which might pose a problem, only for an attack to come out of the blue. Oh, well ...