If you're not bagging your meals, factor in $15-20 for lunch per day. The concession stands and cafes are expensive.
would still cost the same regardless.
But if you're planning the entire trip, then yes food, housing, airfare/transportation...etc...definitely adds up to something much more than $25 per badge.
The concession stands are pretty bad and expensive. You really have to get out of the buildings to recharge. They usually have good Taco trucks out there.