Actually, it's insulin resistance or insulin insufficiency which causes diabetes. Insulin resistence is due to metabolic syndrome, which many obese people have. Insulin insufficiency is when something kills off the islet cells in your pancreas (they think there's an autoimmune component) and you don't secrete enough insulin any more. If I ate that much cake, the only thing I'd get is an awful bellyache. Blarf!
Don't have to google it, I'm a medical professional with over 20 years of experience. You're not exactly wrong, especially if you're talking about white fat vs. brown fat but it not the 'fat surrounding your pancrease' specifically. It's the whole body habitus. Type II diabetes has a few different causes, some genetic, but the most common is general obesity.
"If I eat more cakes...I'll get tooth decay.."
You know what else you're gonna get? Diabetes. ヽ(`Д´)ノ