The Low FODMAP diet?

My GI doctor is trying to help me figure out what's wrong with my digestive system. Without going into the gross details, I started with a colonoscopy which showed nothing wrong.
First step was a probiotic. No change.
Then, I went back on a low-carb diet. Better but not great.
Now I'm supposed to be trying the Low FODMAP diet, which at the outset eliminates anything that could cause fermentation in your gut. Doctor gave me a handout with the good and bad foods listed.
My problem is that this handout is incomplete. So I went looking online for more information.
The problem is that EVERY version of this diet is different! I can't find two that list the same vegetables or dairy foods as acceptable.

Quite frustrating! At this point I'm just trying to eliminate the stuff they all list as bad...taking it one step past low-carb, that means cutting out most artificial sweeteners and broccoli, cauliflower, onions, garlic, avocados and cabbage.

Is there anyone here who can give me some guidance?