There are two main types of diabetes: type 1 and type 2 diabetes.
Type 1 diabetes is an autoimmune condition caused by genetics and unknown environmental factors. Type 2 diabetes is caused by genetics and lifestyle factors. Obesity is one of those lifestyle factors.
Eating more calories than your body needs can lead to obesity. Reducing calorie intake by eliminating concentrated sugars, like sweetened beverages (sweetened teas and coffees, regular sodas, energy and sports drinks), can reduce weight and in turn, reduce risk of developing type 2 diabetes.