This is why working with a nutritionist, at least at first, is so important. I have been on a Low FODMAP diet for two months and I am not eating any of the items you mentioned. No garlic, no onions, no chocolate and very little sugar. That is what happened to me at first. I went to the websites, read the food lists, and started to eat stuff that triggered more diarrhea. The diet starts very restrictive and slowly expands to other foods. It is important to follow a certain method for the diet to work. It is not just a matter of reading a list and start eating Low FODMAP foods. I almost gave up on the diet until I went to see the nutritionist and we adopted a method. Can’t emphasize this enough. It is how foods are first eliminated and then very slowly reintroduced. One can’t just randomly eat all the foods that are listed on the FODMAP diet. The diet must be individualized to your needs and specific problem, I.e., CDiff versus SIBO versus FM. It may be that some people can eventually eat onions again while someone else can never even look at onions again. You may be able to eat very little at first, which is what happened to me. I am very slowly now reintroducing foods. Garlic, onions and chocolate are not even in my horizon at this point. Still, I have not experienced diarrhea in two months and gained 10 of the 20 lbs I lost by following this diet under the supervision of a nutritionist.