Yup. And, we have an entire and huge administration in K-12, paid incredible wages, who have allowed themselves to be the lapdogs of a Federal bureaucracy when each and every minimum wage cafeteria worker knows how to feed the kids better with things they would eat.
Have a look of some around the world:  http://tinyurl.com/world-school-lunches
And, if they don't eat it, then they will be hungry. It would last one or two weeks, and only for the holdouts waiting for "twinkies" (as an analogy).
After that, they'll eat their vegetables, otherwise they'll be hungry.
One of the lessons of school is to grow up. That's not done by an administration that caters to them.
And, by the way, both scenarios would solve childhood obesity while reducing expense for child counselors and psychologists. The nutritionists I would keep. It would be the first time anyone ever listened to them.