When i stand or sit for period of a time (usually upwards of an hour) i get bloated.?

I have had a history with an eating disorder, and I wouldn't say I'm the healthiest eater, but I am at a healthy weight and lifestyle. However, for the last couple of years I haven't been able to sit or stand for extended periods of time with out getting bloated. It doesn't correlate to my meals, as it just comes on whenever the conditions are right (ie. i have been standing for a while or sitting for awhile). It's like a build up of gas in my intestines. Any insight?