In general white carbs, - Rice, bread, heavy cakes, chips, more than a few handfuls of potatoes. Essentially anything that breaks down to a glutenious bolus.
Meats and fish that are too dry.
Fruits with skin
It's all trial and error.
One thing I would say is if you find something that doesn't agree with you first time stay away from it not matter how much you love. The band can be a double edged sword sometimes in that if you really want to get something down you can, but you pay for it with either horrid stomach pains a few hours later or wieght loss that grounds to a sharp halt.