One pretty strong (in my mind) critique of that study I heard on NPR yesterday is that the women who were told to eat the low fat diet weren't told anything about the difference between the bad fats (trans fats) and the good fats (the vegetable ones which actually can HELP control heart disease). So when they cut down--they probably cut down on the good as much as the bad--thus hurting themselves as much as they helped themselves and possibly equalling out to no difference between them and the control group.

Nelie