Why do I get zits if I don't eat any junk food?

Not diet-related. The claim that eating fast food causes acne is politically correct but actually false. You need to manage your acne until it self-cures which can happen at any age. I was able to stop using medication when I was around 50. If toipcal benzoyl peroxide and/or retinoic acid has not cleared you in two weeks, get with your physician.