I hate to be one to agree, but if he's referring to type 2 diabetes, then it's actually a valid point.
Type 2 is not only preventable but reversable (either completely or enough to massively reduce insulin dependency).
This has been known for a while. Even major diabetes organizations and medical universities say it.
The problem is, good luck convincing someone to switch their diet. And if they wanted to, they may not even be able to afford it.
If it were easy, heart disease, cancer, diabetes, and obesity related illnesses would be rare.