I agree that the choices are different in the first world between poor people and people middle class and up. It's the second group of people that I'm claiming are making (or choosing not to think about) this choice.

One can eat equally healthy food for less money, but it is less tasty. I enjoy eating meat, but vegetable protein (beans+rice, etc) is much cheaper. People have the choice to spend less on their own food, and provide more food for other people.

(More caveats: I doubt cutting your food budget is the best place to save money. I favor the giving what we can approach of pledging to give 10% of income and cut wherever you prefer.)