People who opt for a meal at a "healthy" restaurant often consume more calories than they would dining at fast-food joints that make no health claims, a new study shows.
The researchers found that individuals underestimate the calorie content of foods served at restaurants they see as healthier, to a degree that could easily lead to weight gain.
"People think that the same 1,000-calorie meal has 159 fewer calories if it comes from Subway than if it comes from McDonald's," Dr Pierre Chandon, at Institut Européen d'Administration (INSEAD) in Fontainebleau, France, said. "If they choose to consume this fictitious 'calorie credit' on other food, and they eat at Subway twice a week, they could gain an extra 4.9lbs a year."
While restaurants presenting themselves as healthy have grown at a much faster rate over the past five years than traditional fast-food restaurants, Americans' waistlines have not been shrinking, note Chandon and his colleague, Dr Brian Wansink of Cornell University in Ithaca, in their report in the Journal of Consumer Research.
The researchers theorised that people might take in more calories when they eat in "healthy" restaurants and conducted studies to test this notion.
In the first, they asked people who had just finished eating at Subway or McDonald's to estimate how many calories they had consumed. On average, Subway patrons rated their meals as having 151 fewer calories than did McDonald's patrons. In fact, for a meal at either restaurant containing 1,000 calories, people would estimate it to contain 744 calories if they had eaten at McDonald's and 585 calories if they had dined at Subway.
In the second experiment, they asked people to estimate the calorie content of four different sandwiches: a six-inch ham and cheese sandwich (330 calories) and a 12-inch turkey sandwich (600 calories) from Subway, and a McDonald's cheeseburger (330 calories) and a Big Mac (600 calories). Study participants consistently rated the Subway sandwich as having fewer calories than the McDonald's sandwich with the same calorie content.
The researchers also found that people eating the Subway sandwich were more likely to choose a large drink, less likely to opt for diet soda, and more likely to get cookies.