The Accuracy of Stated Energy Contents
"The Accuracy of Stated Energy Contents of Reduced-Energy, Commercially Prepared Foods" is the title of a paper posted in the Journal of the American Dietetic Association and is the nerdy science speak way of saying "the shit on the label isn't so."
The paper (link below) has discovered that the calorie count on labeled food and, more specifically, restaurant foods and frozen meals purchased from supermarkets, were off 8% to 18% on the plus side. To make matters worse some of these values do not include free side dishes. When these were included, calorie count could be off up to 245% on the plus side.
http://www.adajournal.org/article/S0002-8223(09)01679-4/abstract
These findings suggest that stated energy contents of reduced-energy meals obtained from restaurants and supermarkets are not consistently accurate, and in this study averaged more than measured values, especially when free side dishes were taken into account. If widespread, this phenomenon could hamper efforts to self-monitor energy intake to control weight, and could also reduce the potential benefit of recent policy initiatives to disseminate information on food energy content at the point of purchase.