I Have Noticed In The Past Few Months That When

I have noticed in the past few months that when I eat bread, pasta, rice, pizza, drink beer and some others I have issues... With in a few hours I have abdominal pain or diarrhea.. And I always have joint pain the next couple of days... Somedays I can hardly stand up on my feet the pain is so bad... This is new to me about 4 to 6 months... Other then giving up these foods what could this be?