The key to shedding pounds is cutting down on calories, not carbohydrates or proteins, especially among the overweight with type 2 diabetes, a study reveals.

The study, led by Otago University endocrinologist Jeremy Krebs, looked at whether 419 participants (aged 35-75 years) had different rates of weight loss over two years when they were given two low fat diets; one involving high protein intake and the other high in carbohydrates.