Whole wheat, south beach, diet discoveries?

so these past few days ive been posting exercise and diet questions..my most recent one is...everyone says to eat a lot of healthy whole grains? but i just got back from the store and bought a large range of healthy food including boca burgers at only 70 cal per burger :) but of coarse i wanted something to put them on so i started looking at buns and regular white buns only have 110 cal and 10 from fat where as whole wheat has 160 and 25-30 from fat? can anyone tell me why whole wheat is better? and i also realized most south beach diet stuff isnt any lower in cals and carbs then the regular stuff ex. bran crunch 120 cal from sb 100 from special k high protien? anyways plz answer the whole wheat question? has anyone else realized that about south beach? and any other good tasting diet tips?