For health reasons, sure you should include whole wheat, complex carbs in your diet. A large component of that is for fiber. But this is blanket advice...one could well get away with numerous vegetable and achieve the same effect. The difference is eating 1000 calories of bread is a lot easier than 1000 calories of vegetables.

Obviously you can have whole grains. For some people kick starting weight loss is helped by eliminating them for a while. A few individuals will often try and start losing weight by moving from refined carbs to complex carbs, and given the density of whole wheat bread, that will have an adverse effect on your weight.

Michael