Live healthy and work out and you will just do fine. Your weight is no problem and if you go swimming you train all your muscles in a great way. Chips, Coke and Fast food are empty calories they don’t give your body strength and kill your health.
My family had a fastfood restaurant and I grew up on that stuff and earned through that later in life much trouble. Dont eat rubbish food, but eat well you are still growing and your body and especial the development of your brain needs fat. What you dont need it sugar. Sugar is hidden everywhere so instead of having a coke rather press your own juice, drink kefir, milk or plain water. Eat vegetables, fish and meat, good butter but no margarine. If you want to eat sweets, eat rather a dark bitter chocolate then that cheap sweet stuff in the supermarket which is only sugar, fat and little milk. All the sweets and chips have a lot of artificial rubbish and colouring in them which kill your health.
You are young and have your life ahead of you, don’t stress yourself about a diet, everything falls in the right place when you eat healthy and work out. See your body as your friend and ask yourself what is good for my buddy now. A wrong diet in your age can be harmful.
all the best from a old guy from Sweden!