If you can believe it, Pop Tarts are very good snacks while on the run. Runner's World listed them near the top of junk food snacks that are fairly neutral healthwise. They are low fat and have just the right amount of carbs and sugars(same thing) for a long day. I eat them before mid mileage runs.
You cannot go wrong with trail mix(squirrel food) or some training bars. Be careful with training bars. SOme are designed for the high mileage runners or aerobic freaks that burn 6000 cals per session. You can blow up like John Candy if you eat them with no workouts. The good ol Power Bar is a great snack that has a good smattering of vitamins and minerals is doesn't have a whole lot of cals.
Personally I like lobster tail, or some shrimp cocktail, you just have to be carefull not to spill the sauce on the FMS panel. A good Deli sandwhich and potato salad is not too bad cruising along at .82 and FL 410. Fresh brewed coffee or a fruit juice, soda or water will suffice for a drink. We order whatever we want when we cater a flight, when we don't we are sufficiently stocked with snacks, candy, and health food items. Someone remind me is the drinking rule 12 or 8 hours, I always thought it was no drinking within 8 ... feet of an airplane. joke
I get packs of Lance ers like Toastchee and Nekot and carry them with me. I also like granola bars and the packs of mini Chips Ahoy cookies. For breakfast, Kellogg's milk and cereal bars in the Frosted Flake or Fruit Loop flavor.
We carry drinks aboard the plane, so I get a lot of bottled water, a few cokes, and some juice.