I think that people are going a bit overboard with their comparisons regarding what is spent on prison food. People appear not to be thinking about the fact that a prison has to provide more than 1 meal a day.
Don't get me wrong, I think that the amount spent on food in schools is pitiful and applaud anyone who can get it increased (and better food for the kids), but I tend to think that it's not a very good example.
Just my opinion, of course