We often hear how people who want to lose weight are advised to choose when buying foods labeled “fewer calories, but a new study has shown that certain types of commercially prepared foods contain more calories than they  state on the indications.

Food prepared in restaurants and ready-made frozen foods in supermarkets have been studied in Boston, USA. Measured data on the energy values ​​are compared with data on nutrient manufacturer, or employees of stores / restaurants. Restaurants study included the classic restaurants, and places where food can be taken “to go”. By measuring the energy value of food in 29 restaurants they found that the food contains on average 18 percent more calories than the amount that is listed. Similarly, the measured energy value of 10 frozen food products in supermarkets, on average, had 8 percent more calories than the amount referred  in the declaration. The researchers chose products that are sold under the category of food which helps in weight loss and weight control.

During the investigations more unpleasant facts have been discovered. Five of the restaurants were ensuring additional attachments for free. The average energy value of these foods was 471 kcal, which is more than just the starters, with the energy value of 443 kcal. They also found some foods that have had extreme energy values, including three complete meals purchased at the supermarket and seven of restaurant meals contained twice the calories of the above.

The study’s author, Susan B. Roberts , said that in the U.S. is legally allowed to exceed specified energy value of the product for up to 20 percent, but the weight of the product shall not be less than 99 percent above. “These facts can encourage manufacturers to add extra food in the packaging to ensure the standards prescribed weight,” explains Roberts.

The study is published in the January issue of the Journal of the American Dietetic Association .