Food Budget

My wife and I eat pretty well in Spain for about 100 euros a day, sometimes more, sometimes less, so figure 50euro each, or 150 euro.

That gets us coffee and a pastry early morning, more coffee and a snack about 10 or so, a decent sized lunch about 1 or 2 PM, then either tapas at 7 or so, or a moderate/light meal at 8 or 9.

Our costs do include wine or beer, but honestly, both of those are cheaper than soda or other soft drinks.

Keep in mind, if you are planning on eating local, away from tourist areas, then lunch at 1 or 2 is a bigger meal, and the late night eats at 8 or 9 (or later) tend to be lighter. If you just cannot change your eating schedule, there will certainly be places open, in tourist towns a decent selection, but the better places the locals eat will likely not even be open before 8 PM.

Where in Spain?

I usually have dinner in very good restaurants for 50 or less (one person, and these are very good restaurants) and then you have another 50euro for breakfast and lunch. So that's 100 per person per day but there is no way you have to spend that much.
Again, depends on where in Spain..prices can vary a lot depending on destination.

When I go to Spain with my partner, which I do several times a year, I often choose restaurants before hotels. So you can see I am very particular about where I eat. Given that, our most expensive dinner on our last trip was about 110 euro, and it was in a restaurant with one Michelin star and with a small amount of wine. We eat breakfasts in our hotel and are never hungry for lunch.

So If I can get away with 50 per person for top quality meals, for dinner, you can figure it all out.

Breakfast at hotel, or you could do local cafe for 10 euro pp; snacks-tapas-type lunch......

Not sure if all that helps you, but prices for superior food are very reasonable in Spain as compared to the US but again, I don't know your home location.

Take into account that lunch is the main meal in Spain, not dinner. From Monday to Friday, and from around 0130pm to 0330pm, your best option is the "menú del día", which offers a first, a second, a homemade dessert, bread, water and (normally) wine (but you do not have to have it, of course). In the Basque Country and neighboring regions the menú del día includes half a bottle of wine per person. Price ranges from 15 to 20eur p/p, approximately, some places are cheaper, some a bit more expensive, but it´s a great choice for local homemade meals. Not served for dinner, as said before dinner is not that important in Spain.