Which is the most ultimate diet to prevent diabetes?

Any diet: That gets patient to a normal body weight- bmi 20-25 usually means avoiding simple sugars.

Not the key: There is very little science here, since it is impossible to randomize for a prospective study with which people will actually comply. The more you restrict food choices, and the less tasty and high-calorie the food portions, the less people eat. Physical exercise and trimming body fat at key, with exercise probably far more important. I urge you to eat small portions and stay very fit.