My weight is 300 kg.Can i become smart?

These are utterly unrelated characteristics, unless you feel smart means thin -- and it doesn't in English; rather, smart can mean both intelligent and stylish, but not thin.

So I'll take a leap of logic and assume you are asking if you can slim down. Without knowing your gender, age, eating and drinking habits, how much exercise you get, any injuries you have, etc., there is no way to give you anything but an exceptionally generic answer.

Yes, of course you can slim down. Eat less, move more. Talk to your doctor about good nutrition and how to exercise without hurting yourself.

Thanks For Your Nice Anwser...