If you catch type 2 diabetes before it gets so bad that it has killed off the beta cells, then your best treatment is to fast for a while. After a couple of days, you should notice a massive improvement in glucose control. A week of fasting a couple of times a year might be all it takes to give you a complete cure. YMMV, but in my opinion (and that of a whole load of people who know what they're talking about) it's better than filling yourself with drugs.
After the beta cells have been killed off by overwork, yeah, you need insulin. But you can still reduce the amount you need by losing weight.