Paola, good luck with finding the right dietary approach for your son. I recommend you read Professor John Hunter's book Inflammatory Bowel Disease, as he is a UK doctor who uses diet as a primary treatment for crohn's. He goes into a lot of detail about the diet in his book. This dietary approach is specifically formulated for crohn's patients, by a doctor who has spent over 20 years treating IBDers with good success rates. It eliminates a lot of the foods that paleo and other diets eliminate (all dairy and all grains apart from rice are excluded at first, coffee, tea, alcohol, certain fruits and vegetables, and overall fat and fiber are kept at low levels in the beginning as these can be problematic in crohn's). I have had good results on his diet, in that I have been managing to fully control my CD with much milder medication than was initially advised by my doctors.