My mom raised me like you are raising your child. Never, ever gave me any junk food except for chocolate at Christmas and Easter, but she absolutely never allowed any fizzy pop in the house. I will say that whilst she was strict about what we had at home, there was no pressure or expectation to adhere to any restrictions when at parties or friends houses.
We always had very healthy packed lunches as she thought the school dinners were awful.
Anyway, as a PP has responded to you already, I did go mad as a teen. Around 15 or so. Suddenly I had free access to all this delicious junk food, and I'd often buy chocolates or sweets on my way back from school.
But by the time I was 18, the novelty had worn off. My teenage metabolism (god how I'd love that back) meant I was still very skinny, given that aside from my daily binge walking home from school, my meals were all still very healthy thanks to my mom. I went back to the healthy eating habits my mom had instilled in me, and I still eat very healthily to this day.
And whilst I'm partial to a bit of chocolate now and then, I don't see any appeal whatsoever in sweets or fizzy drinks. I really believe this is because the treats we had at home on special occasions were chocolate or homemade cake, never sweets like haribo or anything, so I've just never developed a taste for sweets or fizzy drinks.
My mom always said things like "at least chocolate's got a bit of substance to it, we don't eat sweets because there's nothing to them but sugar and chemicals" - I think she's right tbh!