Sometimes it seems that we're faced with oversized portions at every meal or snack. Fast food places offer us a chance to "up size" our meals. Movie theaters sell gigantic, jumbo tubs of buttery popcorn. Chain restaurants advertise all-you-can-eat dinners. In fact, studies suggest that increased portion sizes are occurring even in our own homes. We've come to assume that giant bagels, enormous muffins and heaping plates of pasta are actually the servings we should be eating.