As for avoiding: red meat (high in omega-6), gluten (chickpea, rice, lentil pasta instead of wheat), cooking with hydrogenated oils, preservatives, processed food, refined sugar
The lists could be much longer. Look up anti-inflammatory diet aka mediterranean diet. What I will say is adhering to this diet has done as much for my inflammatory condition as all the medication. With some foods I feel their effect right away (pork, too much sugar), with some it sneaks up as I let it slip for a few days. So I stand by it.