Parents (in my experience) have three driving forces:
1. Must feed children as much as possible.
2. Must not let food go to waste.
3. Must produce extremely excessive quantities of food.
As you have probably already inferred, this causes problems. Because of the excessive amounts of food, a child does not eat all that exists. This causes wasted food. Which makes parents irate. This is understandable, as they paid money for the food, but they did not have to prepare the food in the first place.
It has happened many times where either my mother or father will come into my room offering dinner, one that I did not request. I go out, have one serving, thank whoever made it, and start making my exit. Then I hear the dreaded word...
"Wait!"
Apparently, I did not have enough of the food. It does not matter that the food was wholly innutritious, that I am not at all hungry, nor that it tasted horrible. If I have one cheeseburger, by gum, I'd better have two. And while I'm at it, why not three? By the time I've had three, one more is hardly anything, and don't even get me started on five. Now, have a sixth one. Consider it a "cool down" lap.
How about just asking me how hungry I am? Saves me a belly ache, and saves you $15. Maybe this is a contributor as to why America is so obese.