Because i am on the road 2 weeks every month I find it hard to avoid fast food and heavy restaurant meals. Now I bring a small cooler or tote with healthy options, such as deli-thin sandwiches made with 98% fat free meats, rfruit and yogurt.
Even when i need to fly, I bring my breakfast or lunch in a small bag, making sure I do not bring any gels or liquids. I always have an empty water bottle and fill it inside the airport security zone. My favorite thing to bring? Pre-measured cereals such as plain cheerios or Kashi.