I went to a dietician who specialized in IBD. She taught me a lot. What to eat, what not, all that good stuff. Went to see her every other week for several months. Now, some say diet does not affect/assist Crohns. Others say diets like the SCD can eliminate symptoms.
Here is what I know. When you have a disease that attacks the digestive system, then it only makes sense to, at the very least, follow a diet that minimizes the stress on your GI tract. That is a no brainer that no one can argue with. Keeping a daily food diary and a follow up with what certain foods do to you, in no time you'll learn what to avoid. Minimizing those foods that aggravate your symptoms, anyone can do that. But learning what to look for (reading labels, understanding what's in the foods you eat via package info, etc..)... that is just one thing you can take away from meeting with a dietician.