(CBS) Are chain restaurants lying to their customers about calorie counts? Most restaurants post calorie counts on their menus and some states even require it. But a new study suggests that nearly one in five of these counts are wrong.
For the study, scientists checked calorie counts of 269 food items from 42 randomly selected fast-food or sit-down restaurants in Massachusetts, Arkansas, and Indiana. They found 40 percent of the food items contained 10 calories more than what was labeled on the menu. Nearly 20 percent of the foods contained more than 100 calories than what was stated in the nutritional facts. One side dish that was studied was off by an egregious 1000 calories.
"You really don't know what you are getting," Dr. Lorien E. Urban, study author and calorie researcher at Tufts University, told Reuters.
100 calories here and there might not seem so outrageous, but according to the study published in the July 20 issue of the Journal of American Medical Association, eating an extra 100 calories everyday can contribute to an added 10 to 30 pounds a year.
What gives? Are restaurants just lying to their customers?
Actually, the authors said, it's mostly a matter of variability in the kitchen. While calorie counts tend to be reasonably accurate for foods prepared and packaged in factories - typical of most fast-food restaurants- counts of foods whipped up right in the restaurant are often off by a wide margin. Why would that be? Because a chef working at a chain restaurant in Massachusetts, for example, might make a bigger plate of spaghetti and meatballs than a cook at the same chain restaurant in California.
"Everybody labels fast food as the bad guys, but they are the good guys in this case - their numbers were much better than those of sit-down restaurants," Roberts told Time.
This study "provides a wake-up call to the restaurant industry, that there's still a long way to go before there is standardization," Dr. Linda Van Horn, author of an accompanying JAMA commentary and a professor of preventive medicine at Northwestern University Feinberg School of Medicine in Chicago, told HealthDay.
It should also be a wake-up call for Americans. More than 30 percent of adults are obese, as are nearly 17 percent of kids and teens. And according to the study authors, almost 35 percent of daily calorie intake comes from restaurants.