Let your children make their own decisions
That's all well and good - when they are old enough to make such decisions. There's a biiiiiig gap between when the damage is done to infants and toddlers and when those children are old enough to make their own minds up.
I'm a bit split on this issue though. One the one hand it does smack of nanny state - but on the other hand there are serious concerns for the health of children who are too young to make their own decisions. Yes, when the child is old enough to stand up to his/her parents and tell them "enough of this rubbish, I'm off down the pizzeria for some proper food" - then they are old enough. Until then I'd say they are deserving of protection.