The federal health care legislation enacted by President Barack Obama last year requires all chain restaurants and food vendors with more than 20 locations to display the number of calories in their foods on menus, drive-thru menus and vending machines by Jan. 1, 2014.

Posting calorie counts is already mandatory in some states and municipalities and those triple and quadruple digit numbers are popping up at an increasing number of restaurants willingly providing the information.

A study by the United States Department of Agriculture reported of the money Americans spent on food in 2009, 42 percent of it was for food away from home.  They also found each meal away from home increased the average calorie intake of adults by 134 calories, which could add up to a two pound weight gain over one year.

However, researchers at New York University and Stanford University are studying whether posting caloric information results in diners making healthier choices, but have found conflicting results.

Even in an encouraging study comparing orders at Starbucks, the researchers found mandatory calorie posting only decreased average calorie consumption by 6 percent – from 247 to 232 calories per order.

Will consumers make healthier choices when faced with the bittersweet truth?