How do i not crave and even eat junkfood?

i cant reallly go on a diet i realized because im only 13, but i have been excersising and TRYING to eat right to lose a few pounds, but whenever i try to eat healthy i always crave junkfood in some point of the day and i always end up eating a whole bunch of it. and thats what im trying to stop. there has to be a way. can someone please help me and please just serious answers thankyou. (: