You might think that customers buying their lunch at McDonald's would order meals with fewer calories if someone handed them a slip of paper reminding them that women should eat no more than 650 calories at lunchtime and men should not exceed 800 calories. But you would be wrong.
Instead, researchers found that diners who received these supposedly helpful reminders actually purchased more calories than those who didn't, according to a new study in the American Journal of Public Health.
The study authors — from the Department of Social and Decision Sciences at Carnegie Mellon University in Pittsburgh and Cornell University's Department of Applied Economics and Management — stood outside two McDonald's restaurants in Manhattan and Brooklyn. They approached diners on their way in and asked them to save their receipts and conduct a short interview after they ate their lunch.