I'm not talking about reinventing the wheel, just some thoughtful engineering. Why choose restaurants that you know do not offer healthy foods. Instead of burger joints look to restaurants where you can build your own meal like Subway and Blimpie. Other restaurants offering a build your own meal like Wendy's allow you to request what condiments coat your sandwich. Choose the light mayo or salad dressing, leave the bacon bits or croutons off, and forget the cheese.
Most restaurants provide a listing of nutritional information for their products.
Ask for this listing. Many times it is posted on a restaurant wall somewhere or in a pamphlet behind the register. Have a look at this information to see where your food choice stands. If you have a bit more time try an establishment that has a salad or food bar. This allows a bit more choice in the matter.