Beans, split peas are all in the legume family. One of their less lovable traits is that, because they're so high in fiber, they cause more gas, and can be painful to us when we're in a flare. I just finally started eating them again after my first year in remission. I love them, but they just hurt me too much.
Beano before you eat will help with the gas, but I still suggest staying away from this group of foods when in a flare.