I have studied numerous diets and healing protocols and animal products* are extremely healing for our guts – especially bone broth/gelatin. Animal products are extremely nutritious and healing!
I cannot provide too much advice in this area but Dr Terry Wahls healed from progressive Multiple Sclerosis with a Paleo Type diet and she has a meat free option in her book. The Wahls Protocol I highly recommend this option for vegetarians and I highly recommend this book for anyone trying to heal from any autoimmune disease including Crohns and Colitis.
*I do want to highlight that all meats should be 100% grass fed, wild caught fish or organic poultry. This is important. Grain fed meats are HIGH inflammatory and unhealthy for anyone with a chronic disease.