I agree with keeping a food diary. Just try a food and see how you feel. I eat very small meals now, but eat more often. It's terrible to not know what to eat, and worse when every book you read says something different.
Dairy never gave me trouble before last month, and it doesn't now. I also love spicy food, so last weekend I had a buffalo wing--just one. No problem. Will I have two wings next time? Maybe.