Leloupaccroupi,
There hasn't been all the much interest in looking at dietary ideas for IBD conditions. Some say that is due to the lack of money to made. I imagine there is some truth to that. I imagine also a good many with IBD conditions are not all that interested in changing their diets and instead rely upon medications.
The most popular diet for IBD conditions is called the SCD. It is similar to the paleo diet. In small studies the SCD was found to help those with Crohns around 60% of the time, to some degree or another. The diet has been around since the 1950s I believe, and despite its popularity it was just announced last month that a large study to look at the SCD for IBD patients was to be conducted.
"First-Ever National Study of Dietary Interventions to Treat Crohn's Disease Receives Funding"
http://www.prnewswire.com/news-rele...rohns-disease-receives-funding-300241074.html
Hopefully the study will be done correctly, meaning there has been a good amount of shady dealings with medication studies. You can read some about that here:
"The Augean stables"
https://drmalcolmkendrick.org/2015/08/27/the-augean-stables/
There doesn't seem to be any hard set rules when it comes to diet. For example, some feel phylum fiber is very helpful for their Crohns. Other find the fiber makes their condition worse. Some find a liquid diet for awhile a great value at letting the stomach heal. One doctor out of the UK, a Dr. Hunter, uses a liquid diet as his starting point to place Crohns patients into remission. From there he works on finding trigger foods that cause problems. His work has been published in several medication journals. Others begin at trying the paleo or SCD diet. Often time the diets help, and sometimes it doesn't. Sometime the diet makes a persons condition worse.
Another popular IBD diet writer is Danielle Walker. She has an IBD condition, believe it to be UC, and she found the paleo diet placed her into remission. She has written a couple New York Times best selling cook books about her IBD diet. One of her books can be viewed here:
"Against All Grain: Delectable Paleo Recipes to Eat Well & Feel Great"
http://www.amazon.com/Against-All-G...&qid=1461234780&sr=8-2&keywords=daniel+walker