Melissa, I have suffered from IBS for over 40 years and along the way, I found out I was allergic to Cottonseed oil.
So I have to read the ingredients on everything I buy. My thoughts are people are allergic to certain foods and it is very hard to find out just what.
You have to write down what each meal consists of. Then when you have an attack, keep that one to check out when the next one occurs. Then mabe you can pick out just what part of the meal matched the one you kept a log on. If you keep doing this, you probably will find the one food or two that is trigering your attacks.
I had ice cream at home years ago, and within an hour, I was deathly sick, severe cramps, broke out in cold sweats and then vomiting. Turned out to be Cottonseed Oil for me.