Too easy. Homewood Suites or Residence Inn have stocked kitchens. Buy everything for the week when you hit town, store in the fridge, and cook every night.
Don't eat downstairs for breakfast. Cook real eggs in the room or oats with protein powder and skim milk.
Fruits and veggies or a shake between meals. Bags of tuna are cheap and extremely easy to carry around. Take a fork from breakfast downstairs and throw 2-3 tunas into whatever you're carrying.
If you go out order a la carte. I have yet to go to a place that won't do that for me. Almost always fish is the night's special because it won't keep as long. I order the special with an 8 oz filet on the side (I've never paid more than six additional dollars for a filet - can you believe that?) and double veggies vice rice or potato. If we go somewhere nice I order a chicken breast, filet, and a salad with dressing on the side.
Airports suck ass. I always bring along a handful of protein bars. They will make you fat but it's a hell of a lot better than eating that shit being served in the airport.
I eat best on the road. It's entirely too easy.