Is diabetics controllable?
Yes, it's possible, but it depends on the type of diabets. The most common recommendations are improving diet and small increases in activity (sometimes loosing some pounds could give good results), redusing stress level. And don't forget about blood pressure, for most people with diabetes ideal BP is below 140/90.
Please take note of these articles explaining about diabetes:
Spider's web inspires removable implant that may control type 1 diabetes
Pain-free skin patch responds to sugar levels for management of type 2 diabetes
http://www.ard-ng.org/2017/12/28/pain-free-skin-patch-responds-to-sugar-levels-for-management-of-type-2-diabetes/