It's the FODMAPs in food that affect you, so you really need to be able to drill down to undertand what is in each food item. The app is really helpful for this, as it will show you what is in each food. Then you can work out triggers from there.
For example: Broccoli
Whole vegetable
FODMAP rating: LOW overall at a typical serve of 1 cup.
Heads only
FODMAP rating: LOW overall at a typical serve of 1 cup.
Stalks only
FODMAP rating: HIGH in excess fructose at a typical serve of 1 cup, but LOW at a smaller serve of ½ cup.
Summary: In regular broccoli, the main FODMAP present is excess fructose and this is found predominantly in the stalks. Avoid large servings of broccoli stalks alone (>65g) if you are sensitive to excess fructose (use whole broccoli instead)
FODMAPs are:
Fermentable - Process through which gut bacteria ferment undigested carbohydrate to produce gases.
Oligosaccharides - Fructans & GOS - found in foods such as wheat, rye, onions, garlic and legumes/pulses.
Disaccharides - Lactose - found in dairy products like milk, soft cheeses and yogurts.
Monosaccharides - Fructose - found in honey, apples, high fructose corn syrups, etc.
Polyols - Sorbitol and Mannitol - Found in some fruit and vegetables and used as artificial sweeteners.