You checked online, so you think you know how many calories are in that restaurant taco salad. Think again. A new study shows that meals eaten out might contain more calories than restaurants report.
Researchers at Tufts University analyzed the calorie content of food from quick-serve and sit-down restaurants as well as prepared, frozen supermarket meals. They tested 29 restaurant items and found that, on average, the calorie content of the food was 18 percent higher than the reported values and 8 percent higher in 10 frozen meals tested.
The report, published in the current issue of the Journal of the American Dietetic Association, adds a new mine field to the battle of the bulge.
“I think the biggest lesson is simply the finding that calories eaten out are probably more than you think,” said senior study author Susan B. Roberts, professor of nutrition at Tufts, in Boston, and author of The "I" Diet. “In America today, when so many of us are so weight-challenged, that really is a problem.”
Researchers purposely chose items with some of the lowest calorie contents on the menus to make the study more relevant to those trying to lose weight.
In terms of methodology, researchers compared the gross energy, or total calorie content, of a dish when measured in the lab to the restaurant-reported calorie information for that dish.
When companies report nutrition facts, the number of calories represent metabolizable energy, or the calories available for use by the body. This is calculated by subtracting the calories a person is expected to excrete from the gross calories in a food item. Metabolizable calorie counts are lower than gross calorie counts. But using the metabolizable count is in compliance with Food and Drug Administration regulations for nutrition reporting.
Because restaurants gave figures for metabolizable calories, the researchers converted that number to gross calories to ensure accuracy by comparing the same units.
The team analyzed an assortment of dishes from restaurants ranging from Taco Bell to P.F. Chang’s. No foods or restaurants were specifically singled out and some resturants, including McDonald's, had accurate counts based on total calories of items.
“We were just looking for average problems,” Roberts said, rather than trying to assess whether any particular restaurant was good or bad about nutrition reporting.
P.F. Chang’s has chosen not to make a formal statement regarding the study, according to Rachel Gillman, spokeswoman for the chain. Calls to the corporate headquarters of Denny's, another resturant included in the chain, were not returned by deadline.
While, on average, calorie contents measured in the study were 18 percent higher in restaurant foods, individual calorie counts varied widely. Some dishes actually contained fewer calories, but some had almost double the stated amount.
“It can definitely take its toll, especially if people have to have fast food [on the go] and places are giving inaccurate information,” said Marisa Bobbe, a registered dietician in Chicago. “That’s detrimental to weight loss. That’s really absurd.”
At many restaurants, the researchers found consumers were given larger portion sizes than those used by the restaurants to determine the calorie content of their food. The team made further calculations to account for the portion discrepancies.
“We were looking to see how much was the fault of the ingredients versus the portion size,” Roberts said. “It seemed to be a combination of the two things. Partly they were giving bigger portions, and partly I think there were more high-calorie ingredients.”
So who is accountable?
Siobhan DeLancey, a spokeswoman for the FDA, said she knows of no plan for the agency to expand jurisdiction to cover restaurants. This is partly because determining a restaurant food's exact profile is difficult when a dish can vary based upon the individual preparing it or the particular ingredients that are available at the time, DeLancey said.
“I think it’s the restaurants’ responsibility,” Bobbe said. “Most restaurants have plenty of measuring utensils and they’re more than capable of measuring their foods. But it’s also the consumer’s responsibility to think. I’d say it’s 50-50.”