Starting this week,are required to be posted at restaurants and fast-food outlets with more than 20 locations. It's all part of a labeling requirement included in the Affordable Care Act that was passed in 2010, with the goal of encouraging people to make healthier food choices. Some large chains started putting calorie information on their menus at that time, but it's now required.
The question is: Does seeing the calorie count actually change what we order?
"The research shows that for most people, no," Lisa Harnack, a nutritional epidemiologist with the University of Minnesota School of Public Health, told CBS Minnesota. "We find that people tend to think nutrition is less important when they're eating out than when they're grocery shopping. So they may think, oh, it's a special occasion, I don't need to worry."
was one of the first restaurants chains to post calorie information on its menus in 2010.
"We noticed customers looking for that information will change what they order, but it's usually the customers looking for it in the first place," said Panera dietitian Katie Kriegshauser.
One study questioned New Yorkers who ate at fast-food restaurants in 2013 (after labeling began there) and compared their answers to a survey done in 2008 (before labeling). Those researchers found no change in calories consumed.
Another study used information fromtransactions and found calorie consumption dropped 6 percent.
"The effect is almost entirely related to changes in consumers' food choices – there is almost no change in purchases of beverage calories," the study's authors wrote.
Another potential impact of posting calories could be that restaurants change their menu options to include healthier choices, but Harnack says that will require further study.
Harnack says this is a difficult topic to research because only a few large chains have posted calorie information to date, and people are also notoriously bad a estimating their calorie intake.
She says much more research will be done now that the new calorie requirements are in place.
"As a researcher, this is a very exciting day," she says.
In general, experts recommend eating about 2,000 calories a day for women and 2,500 calories a day for men, but given America's obesity problem, it's clear many people are getting far more than that. For more information on how many calories, protein, sugar and dairy an individual should eat, visit this website from the U.S. Department of Agriculture.