The old saying “let the buyer beware” is a great guidepost for consumers.

But what if they ignore helpful information?

That’s the dilemma posed by a recent study in the journal Health Affairs, which focused on calorie labeling in fast-food restaurants.

Researchers investigated the effects of a New York City law requiring chain restaurants to post the calorie content of all menu items.

Apparently, the information didn’t motivate people to eat lighter.

In the study, researchers interviewed customers at four fast-food chains in low-income minority neighborhoods.

Research was done before and after the labeling law took effect. Another arm of the study was done in a nearby city with no labeling law, Newark, New Jersey.

Customers were approached as they entered a restaurant. Researchers collected data about their purchases and demographics.

Among participants in New York after the labeling law took effect, about one-fourth said calorie information influenced their choices. Most of that group BELIEVED they picked lower-calorie items.

But their receipts told a different story.

Actually, they ate about the same number of calories as diners in New York before the labeling law took effect, and those in Newark.

Despite these findings, the researchers concluded that calorie-labeling mandates aren’t necessarily ineffective.

They could be useful to savvy customers, and might inspire chain restaurants to offer healthier options.

But the study seems to demonstrate the power of wishful thinking.

Remember… just because you think a menu option is healthy, doesn’t make it so.

When in doubt, check the label.

Maybe that piece of consumer wisdom needs to get more attention.