The energy contents of individual foods are given in the , and illustrates percent differences between measured and stated values. On average, restaurant foods contained 18% more energy than stated; however, there was substantial variability in the difference between measured and stated values, and some foods contained twice as much energy as stated. The measured energy content of supermarket-purchased meals was also greater than stated values, by 8%. There was no statistically significant difference between measured and stated values in either restaurant foods (P = 0.12) or supermarket meals (P = 0.12), and no significant difference between the mean accuracy of restaurant vs supermarket foods (P = 0.64). However, the difference between the standard deviation of the energy discrepancies in restaurant vs supermarket foods approached significance (P = 0.06) and became significant once the energy discrepancies were adjusted for discrepancies of portion size (P = 0.05). Thus, there is more uncertainty regarding stated energy values in restaurant foods than in supermarket packaged foods. Five restaurants provided side dishes at no extra cost. The mean additional energy provided by these items was 471 ± 167 kcal, which was greater than the 443 kcal mean value for the entrées they accompanied. Portion size discrepancies (measured minus stated values) were a significant predictor of percent energy difference between measured and stated energy contents values when added to the model predicting provided food energy (P <0.0001), indicating that greater portions than stated did contribute to the energy discrepancy.
Nutrients and energy in reduced-energy meals ordered from restaurants and convenience meals purchased in supermarkets
Measured energy amounts in selected reduced-energy restaurant foods (panel A) and supermarket convenience meals (panel B). GE = gross energy. Numbers correspond to restaurant or supermarket food items shown in the .
There was no statistically significant association between differences in measured vs stated energy based on whether the item was a side dish or an entrée, type of restaurant (quick-serve or sit-down), meal at which the food is usually consumed (breakfast or lunch/dinner), restaurant size (number of franchises), cost per unit calculated energy content, or where the meal was purchased (restaurant or supermarket). It should also be noted that, since single samples of each food were obtained, the variability in results pertains to the general sample of foods studied, and individual results cannot be attributed to specific restaurants and brands of foods.
These results indicate that, in contrast to two recent reports in the media (17
), restaurant meals and prepared meals purchased in US supermarkets do not typically contain substantially more energy than stated. However, measured energy values did average 18% higher in restaurant foods and 8% higher in supermarket meals than stated. The underreporting of energy by restaurants and food manufacturers notwithstanding, the majority of foods tested were not out of compliance with US Food and Drug Administration regulations because most fell within the 20% overage the Administration allows for packaged food (no ceiling of overage is specified for restaurant foods). In relation to this observation, it should be noted that, as outlined in , the US Food and Drug Administration considers noncompliance in packaged foods to include food energy (average of 12 samples) in excess of 120% of stated energy or <99% of stated weight (average of 48 samples) (26
), which because of greater leniency in standards on the side of overprovision compared to underprovision, may contribute to provided energy values being greater than measured. It should also be noted that three individual supermarket-purchased meals and seven restaurant foods did contain up to twice the stated energy, so some individual discrepancies were substantial.
Summary of US Food and Drug Administration regulations on nutrition labeling in relation to energy.
The extra mean measured energy in this study compared to stated information may cause substantial weight gain over time. For example, positive energy balance of only 5% per day for an individual requiring 2,000 kcal/day could lead to a 10-lb weight gain in a single year. It is also notable that free side dishes on average contained more energy than the entrées alone. It is unclear whether consumers are aware of how much energy free side dishes contain, and providing more accessible information on meal energy contents both with and without side dishes could help increase attention to the potential of these casual food items to more than double meal energy intake.