If they're taking Metformin...they've got diabetes. Lots of type 2 diabetics are on diet control to try and keep from taking meds.
I like the diet idea. I used to have to pee so much driving in the morning that people thought I might need to get checked for diabetes (my grandfather had it). That can really be a burden in this gig. But I switched to decaf and it's seemed to make a big difference.