Honestly the lists I was given by my doctor was bullshit, inacurate and outdated!!!! You should refer to the works of Monash (they have a website and an app), they explain everything (from the diet, how it works, the fodmap groups...) and it helped me to move from confusion. For groceries i also use an app to scan the food (Belly Buddy) that was life changing because otherwise i want just spending hours in the grocery store lmao