Researchers from Carnegie Mellon University found that when people were given calorie suggestions at McDonald’s — including recommended calories per meal, as well as recommended calories per day — they consumed no fewer calories than if they were given no calorie advice at all.
“There have been high hopes that menu labeling could be a key tool to help combat high obesity levels in this country, and many people do appreciate having that information available,” study researcher Julie Downs, an associate research professor of social and decision sciences in the university’s Dietrich College of Humanities and Social Sciences, said in a statement.
“Unfortunately, this approach doesn’t appear to be helping to reduce consumption very much, even when we give consumers what policymakers thought might help: some guidance for how many calories they should be eating,” she added.
The study, published in the American Journal of Public Health, included 1,121 adults who dined during lunchtime at two New York City McDonald’s restaurants (researchers timed their study so that they could gather data prior to and following 2008 menu labeling regulations). The participants were given information on recommended calorie intake per day (2,000 calories for women or 2,400 calories for men), recommended calorie intake per meal (650 calories per meal for women, or 800 calories per meal for men), or no calorie recommendations at all.
Researchers asked the participants to answer a survey, where they estimated the amount of calories their meal that day had, whether they actually looked at and considered the menu calorie information, as well as how many calories they thought “a doctor or nutritionist would recommend that you should eat for your daily diet.”
Researchers found that “providing calorie recommendation benchmarks — such as calories per day or calories per meal — did not reduce calories purchased, nor did it appear to help participants to better use the calorie information posted on menus,” they wrote in the study. “In fact, we found some evidence that recommendations may even have promoted purchase of higher-calorie items.”
Previously, research has hinted that calorie postings on menus may not alter buying behavior of consumers. A study from New York University researchers showed back in 2011 that teens didn’t necessarily buy fewer calories even if they saw menu calorie counts, TIME reported. However, another study on teens from low-income neighborhoods showed that calorie information seemed to spur teens to be less likely to buy full-calorie drinks.
Something that could work better than calories at changing buying behavior? Posting exercise equivalents for food, according to a recent op-ed in the New England Journal of Medicine.