I'm probably inviting flames but I do eat junk in front of my LOs sometimes (although I do tend to sneak it) and I don't have any problem telling them why I can and they can't.
My body is done growing...theres are not.
Most of what we all put in our bodies should be wholesome, but especially for growing children. And when you are little, a little junk ends up being a much bigger percentage of what they take in.
So, they do get some...but not as often as I do...