I’ve seen a friend diagnosed with type 2 diabetes return his insulin levels to normal through diet, exercise and cutting out alcohol. It just takes more discipline than most people have. Edit: I’m presuming he had T2 because he didn’t get it as a child, but reading this thread I see T1 can be diagnosed as an adult: I did not know that.

Honestly I am trying to have the same discipline myself after seeing the results, because I wish to avoid the harmful effects of a poor diet and get the benefits of a good one. I am not managing to do it yet - and I’m not sure a health scare would motivate me enough either...