The first thing you have to keep in mind is that truckers, due to the nature of their profession, are sitting around a lot.  What happens when we sit around too often?  We don't burn many calories.  Those unused calories get stored as fat.  It would be best to cut down on calories.  This means that when you stop to eat, you should focus on eating grilled foods or salads with no dressing.  To drink, order iced water, plain iced tea, or plain coffee.  

Most truckers have a schedule when they're working for part of the week, and then have the rest of the week off.  These rest days are good times to get in some cardiovascular exercise and strength training.  The strength training is essential as muscle increases your metabolic rate.  If that's not possible, join a national fitness center, especially one that's open 24 hours.  It's also a good idea (when pulled over, of course) to stretch and do jumping jacks.  Another important part of a trucker's diet is taking multivitamins.

Truckers, like most Americans, have to deal with rising gas prices.   In the works now is a tax credit for truckers to buy different types of fuel than diesel.  This allows truckers to turn off their rigs and keep warm or cool.  Another way to cut down on costs is by combining trips, taking shorter routes to your destination, going under the speed limit, and keeping as small a load as possible in the vehicle.  

Last, but not least, are pets.  Truckers, unlike most other professionals, can take pets to work.  As long as the pet is small, there should be enough room in the truck.  Also, the pet needs frequent breaks and stops to get rejuvenated.