help needed ibs

I would talk to your doctor more in depth about the issue. They typically have a course of action that they recommend, but there is a great resource through the Gastrointestinal Disorders Foundation (http://www.aboutibs.org/site/treatment/diet/) that talks about the causes and some tips for potentially lessening symptoms. Unfortunately, not all IBS is even tied to what you eat

IBS is a very individualised condition when it comes to what food aggravates it. I have had IBS for twenty years now and the only things I couldn't tolerate for the majority of that time were pasta and if I ate too much bread/potato. Cue bloating and frequent toilet trips. I was absolutely fine with spicy food, vegetables, fruit and coffee. In the last year however I can no longer tolerate bananas or coffee, (I loved coffee!!!). The symptoms are not as severe but the bloating was just unbelievable. I totally agree with @jgnatca you will need to 'trial and error it' as what suits you may not suit another individual and vice versa. Listen to your body.
Having said that I never had an issue with losing weight as the same premise is there CICO - calories in v calories out!

Good luck!