I would wait to see what time you clear customs to decide when to head to the airport. If you blew through customs you could potentially have 4 hours before your flight. If the airport happens to not be busy, you will be sitting around for a very long time with really crappy food choices. If you don't think you have time for a potentially long sit down lunch, I would suggest Bumpa's in town. They are a quick, order at the counter place that does really good food. Whatever you do, don't go to that airport 4 hours ahead on an empty stomach.