Does knowing the number of calories in your food matter?

Since the FDA recently finalized rulesrequiring all chain restaurants to post the number of calories in their food on the menu, it’s worth discussing whether knowing the amount of calories in that donut will deter you from eating it.

These rules are required by the Affordable Care Act, took four years to put together and are more strongly worded than previous iterations — but that doesn’t necessarily mean they’re going to make a dent in the country’s obesity problem.

Posting calorie counts is not a new concept– in fact, many cities and counties require their restaurants to do it already. The number crunchers over at FiveThirtyEight took a look at some research done on the subject and found that studies haven’t been able to prove that calorie counts change what people order. Here are some of the highlights:

• In one 2008 study, researchers compared the change in how many calories people purchased in New York before and after the calorie counts were posted. While 30 percent of people surveyed said the calorie postings affected their choice, in reality there was no difference in the number of calories they purchased.• Randomized laboratory experiments proved the same thing: People randomly selected to order from a menu with calorie counts did not order fewer calories than people whose menus had no such information.

But why aren’t people choosing the healthier options more often, even when we’ve made it so easy for them?

In a 2009 paper published in the Journal of Consumer Research — and checked out by the New York Times — researchers at Baruch College found evidence that including some healthy items on a menu actually influences some people to order junk food.

In the study, college students were given one of two menus: One had stuff like chicken nuggets and fries, and the other had the same junk plus a salad. More than 30 percent of the students given the salad menu chose the fries– compared to just ten percent of the all junk menu recipients.

Why?

“When you consider the healthy option, you say, well, I could have that option,” one of the scientists involved in the study told the New York Times. “That lowers your guard, leading to self-indulgent behavior.”

So maybe there is similar relationship between knowing how healthy something is, i.e. if its calorie count is posted, and choosing not to order it.