Here are some pointers when working with tortillas:
Fat: The type of shortening used to make tortillas can be a source of concern. Lard, of course, is the age-old staple but its cholesterol content and high percentage of saturated fat pose obvious problems. Versions made with "pure vegetable shortening" still conceal saturated fat. If you're really concerned, shop for brands including "partially hydrogenated vegetable oil," just plain vegetable oil. But the latter tend to be thicker and heavier.
Corn tortillas are generally made without added fat.
Flour: Whole-wheat tortillas lend fiber to the diet. So do corn tortillas; they have the added benefit that corn and beans provide complementary proteins which, when consumed during the same day, are equivalent to meat. However, plain flour tortillas have a more neutral flavor and tend to fold more easily when wrapping burritos, chimichangas, etc.