I have just started bringing Indian food with me on trips and it has been a superb change up. Any store that has a good ethnic food section (I shop at Whole Foods) should have decent selection of poplular packaged, ready to heat Indian dishes. They come in flat foil pouches and take up very little room. They cost about $3.50 and give you about the same amount of food as a can of soup. To complete the experience, I also get some Naan (Indian flat bread) to scoop up my meal and it doesn't smoosh in the lunchbox. And since all you need is coffee pot to warm them up in, I keep a couple in my laptop bag in case schedule changes or delays prevent me from packing dinner. I also do all the other things mentioned, but this new discovery has been a real life saver.

If you have acess to a crew room fridge, cook for the trip the night prior (Pasta, chicken and rice etc.) and store single meals in ziplock containers and nuke them as you need them. You get looks like you are about to enter the wildnerness for six months but it seriously cuts down on the processed foods and sodium.