As a medic student, I've got to say that I'm not particularly successful at eating healthy, though I think I've found some good ways to side-step it a little. If you always go out somewhere, then one good way to dodge about 20 teaspoons of sugar, enough caffeine to kill a small horse, and several hundred calories is to pass on the soda altogether and order a bottled water instead. Another good way- at least, if you can get people at the drive-thru that actually listen- is to request your sandwiches without the mayo, sauces, etc on them and save yourself from a supermassive MI down the road. Another way to success is to avoid breaded foods, since that breading soaks up gallons of grease (they probably would've resolved the Exxon-Valdez incident a lot faster if they'd just thrown some breading out there).
Also, I've taken up the habit of doing enough weight training to burn into my glycogen stores (about 30 mins of weight-training) and then walking at a solid 3 mph for 90 to 120 minutes in my spare time. Haven't seen any weight loss yet, but I've just started. At least I feel noticably better.