You can hammer your overweight patients ad infinitum about the ways in which obesity compromises heart function. Or you can give them a simple experiment to try: Ask them to stop on their way home from your office first at a large supermarket, and then at the nearest health food market. They don’t have to buy anything, only ask themselves who they would prefer to look like: the people at the supermarket or the people in the health food store? “This can be very convincing,” said Dr. Weiss.