Pemmican is easily transportable.  Bags of pork rinds are nice.  Macadamia
nuts keep well at room temperature.  Getting a steak from the dining cart
may be a little pricy.  If there is anything buffet-like you will have to
watch it.  It takes a while before dietary self-controll is internalized in
kids.  (However, if you start young enough, there is a natural "disgust"
mechanism in humans that keeps people from eating foods that are not
consumed in youth - thus we don't eat bugs even though they are good for
us).