I have been working with the geriatric population since 1988. I have actually seen more thin to average size type II diabetics than heavy type II diabetics.
This is one of those diseases that becomes more likely as a person ages. The fatphobia in our current medical system means that larger people who may happen to be at risk aren’t getting the treatment they need because they’re ashamed to seek treatment. It also means that the disease may be being missed in people with smaller body types, because “only fatties get type II diabetes.”
Fat hate is helping no-one of any size.