I'm thinking of throwing away my parents' sugary snacks.
Do you think sugar is bad for you?
Yes, I found out sugar is for human consumption only when it's in its natural state, like fruits.
It's nice that you want your parents to be healthy. It's not really okay to control a parent's diet, though. They'll probably just be annoyed and buy more.
So that's it, I'm going to force them to stop eating sugar.
You sound like you really care about your parents and that's great, but if you do this then they'll just become angry with you and buy new snacks. It'd be best to explain to them that you think sugar is wrong and open up a conversation about how they could be eating healthier.