Insulin is only responsible for making human look small or big,isnt it?

Insulin is only responsible for making human look small or big,isnt it? i think when we eat and that convert into glucose then it burn then remainning is goin to store as a fat or muscle......if i m not mistaking so what will happean if ur body stop producing insulin ...will u get body builder by storing fats??????/ also i m taking high carbs diet ....4000 cals a day...suggest me...in detail