Without wishing to get in a real pi55ing contest abouts terms of employment etc but the big difference as far as I can tell between military cook house food prices and civilian canteen food prices is that the military are not trying to make a profit. The £x the head military chef got each day all went into the food and
may reflect the true cost
of the food therefore the £x
plus y that you pay in the civilian canteen is all profit (granted there would also be an element of staff costs that the military may reflect in another bidget on the basis of "warfighter first, slop jockey second"). Bottom line when you join any company what "perks" you receive on day 1 is your personal baseline. If you don't like subsequent changes then leave - believe me the erosion in military "T&Cs" is one of the big factors that is being quoted by those leaving, whether it be the amount you pay for food, the standard of the military housing, or the fact that you just can't get decent stabling for your Polo ponies
