type 2 diabetes is built up over time and is caused by a pituitary gland that is not functioning optimally. over time due to poor diet choices, which is frequent meal timing they develop and insulin resistance. this causes their blood sugar to rise more and more to the point where they will need a drug or insulin to drop it down especially after meals.
if you get your fasting bloods checked and your G is over 100 you need to start changing the way you eat. and it isn't just about WHAT YOU EAT, although that is very important, it is also HOW OFTEN you eat. we are taught nowadays to eat every 2 hours and that is leading to a blowup in diabetes.. the US leads the world in diabetes because of how we eat and how often we eat
and yes if you are fat you are going to be more likely to become diabetic.. it is more the means than the cause. a fat person probably eats poorly hence is more likely to get not just diabetes but also heart disease and cancer