The best thing you can do for your (type 2) diabetes is gaining muscle mass. The musculature plays a big role for taking up sugar from the blood and when you have little muscle mass, your pancreas tries to compensate by flooding the blood with insulin. This doesn't work long term, and ultimately two things happen, the insulin has a lower effect on the muscle, and the production of insulin itself is lowered cuz your beta-cells of the langerhans islets are "exhausted"
Reducing calories, and rapidly absorbable carbs is beneficial, but it is kinda different to reduce the intake when you ain't moving your bum. Reason: the stomach ain't even distended enough to give you the feeling of fullness before you have exceeded your diet plans if you don't start excercising.
I am talking bout type 2 diabetics here, which means the most of you, the poor chaps with the type 1 needs exogenous insulin, period. But you guys can actually do something about your disease, and guess what: it's free. Second fact, it takes more than 5 min a day. Lose weight with endurance training and gain muscle by lifting weights. Then afterwards, start bi**hing about the diet.