I have had IBS-D for over 40 years. I have been gluten free for 13 years and it's helped but I still get days when I can't leave the house. Was tested for SIBO years ago and it came out that I made methane gas. Which is odd since methane gas is supposed to make you constipated. I have used the Fodmap diet to guide me. I stay away from gluten and dairy products but still have problems. I do feel better if I don't eat a lot at one meal.