What I find a bit sad is the "cure > prevention" attitude. The cause of pre-diabetes & type 2 diabetes is pretty well known now, i.e. it's basically the inability of body stores (liver/muscle glycogen stores & fat masses) to accommodate any more, resulting in excessive amounts of various things (e.g. glucose, fat, cholesterol, NEFAs etc) in the blood, with varying degrees of beta cell dysfunction.
The degree of fatness at which body stores become full depends on the degree of adipocyte hyperplasia, so it's possible for slim people to become type 2 diabetic, though ~85% of type 2 diabetics are over-fat. Some slim people are misdiagnosed with type 2 diabetes, as they have LADA or signalling abnormalities. Some have acquired endocrine abnormalities.
I've been pre-diabetic twice to my knowledge, the most recent occasion being last year when I became slightly manic after mum died and got into a large number of arguments on various blogs. I "took my eye off the ball" diet-wise and ended up gaining too much body-fat, even though my belt didn't feel noticeably tight. I blogged about feeling too hot last year. When I had blood tests in September to find out why I was overheating so much, the results revealed hyper****aemia, where **** = glucose, total cholesterol & triglycerides. The doctor recommended that I take a statin. I declined, stating that I knew what had caused the problem and that I would deal with it. I was told to have repeat blood tests in 3 months time.
I subsequently "kept my eye on the ball" diet-wise (using bathroom scales to monitor progress), lost 8kg (some of it fat mass & some of it muscle mass) and when I was retested 3 months later, the previously abnormal blood test results were back to completely normal. That's twice I've gone from pre-diabetes to normal, which suggests that deterioration from pre-diabetes to type 2 diabetes is not inevitable, provided that the cause is dealt with before excessive irreversible beta cell dysfunction occurs.
The main reason why the incidence of over-fatness & type 2 diabetes is increasing is the overconsumption of "Crap in a bag/box/bottle" by increasing numbers of people. How to reverse this trend? Damned if I know!