Getting food at a major airport is not a usually a story with a happy ending. Most airport foods tends to be too fatty, too salty, not fresh and grossly overpriced.
There are refuges such as the odd sushi restaurant or the burritos place at Dallas Airport. The American Express Centurion lounges are often sacred places for the food refugee, offering healthy and fresh cuisine at restaurant-standard for free to Platinum and Centurion cardholders.
I recently toured Rome's Fiumicino Airport and found a number of delicious (although not necessarily healthy) food options at a fair price level.
Here are some pictures highlighting the available cuisine at the airport. So maybe this is an airport you'd be willing to go to (or stop over at) just for a delicious meal finally?