I also pinch and save some money for my eating expenditures and keep to eating lunches instead of dinners when I go out.
When traveling, I eat canned food, ramen noodles, and pizza in the hotel room for dinner. The coffee maker in the hotel room is my friend. I always bring packets of Quaker cereal, chamomile tea, and Cup o' Noodles so that I can get hot breakfast and some dinners covered at the minimum fixed cost. I also carve out time grocery shopping at local markets for local products or region-specific imports, park my car in a state park, and picnic in my rental car. That way, you can do better than $40 a day when you average out your vacation days.
So note: The coffeemaker can be used to heat up food, and the free ice and ice bucket can be used as a small fridge.
Pizza from Pizza Hut; $2 canned yummy seafood imported from Spain makes a great side dish for a bowl of ramen in the hotel room
2 Jumbo Stone Crab Claws (as big as they get) for $21.89 total from the grocery store vs. at a restaurant for"market price" + 15-20% tip
crab claw + box of sushi = an affordable seafood meal (considering how the claw is really a luxury item)
Sharing a to-go Cuban Sandwich and a whole fried red snapper from La Carreta (12 Crandon Blvd, Key Biscayne, FL 33149) at a scenic highway rest area in Key Biscayne.
Drinking mango juice imported from Guatemala and coconut water from I forget where both at 3 boxes for $0.99. Hell yeah.