ARS | Publication request: The accuracy of stated energy contents of reduced-energy, commercially prepared foods

Submitted to: American Dietetic Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 3, 2009
Publication Date: January 1, 2010
Citation: Urban, L., Dallal, G.E., Robinson, L., Ausman, L., Saltzman, E., Roberts, S.B. 2010. The accuracy of stated energy contents of reduced-energy, commercially Prepared Foods. American Dietetic Association. 110:116-123.

Interpretive Summary: Americans are currently eating approximately one-third of their meals away from home, and many people use calorie information stated on packaged foods or on restaurant websites to help manage their weight. This along with the rising prevalence of obesity and the recent policy initiatives to include calorie information on restaurant menus underscores the importance that stated calorie information be accurate. In this study, the accuracy of stated calories for reduced-energy restaurant foods and frozen meals purchased from supermarkets was evaluated. Calories measured by bomb calorimetry in the laboratory averaged 18% more than the calories stated on restaurant websites for the 29 quick-serve and sit-down restaurant foods included in the study. Laboratory measured energy values of the 10 frozen meals purchased from supermarkets averaged 8% more than what was stated on the packages. These differences substantially exceeded laboratory measurement error but did not achieve statistical significance due to considerable variability in the degree of underreporting. Some individual restaurant items contained up to 200% of stated values and, in addition, free side dishes increased provided energy to an average of 245% of stated values for the entrees they accompanied. 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.

Technical Abstract: The accuracy of stated energy contents of reduced calorie restaurant foods and frozen meals purchased from supermarkets was evaluated. Measured energy values of 29 quick-serve and sit-down restaurant foods averaged 18% more than stated values, and measured energy values of 10 frozen meals purchased from supermarkets averaged 8% more than originally stated. These differences substantially exceeded laboratory measurement error but did not achieve statistical significance due to considerable variability in the degree of underreporting. Some individual restaurant items contained up to 200% of stated values and, in addition, free side dishes increased provided energy to an average of 245% of stated values for the entrees they accompanied. These findings suggest that stated energy contents of reduced calorie 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 calorie 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.