If you post calorie counts on your menu, it's not in vain: that information is shaping what your customers are ordering.

According to a recent survey by the Centers for Disease Control and Prevention, 57 percent of people use calorie counts, when available, to decide what to order at fast food and chain restaurants. Twelve percent of customers self-report that they always use menu labeling information when it is available.

Across the 17 states surveyed by the CDC, women were more likely than men to use menu labeling, with 66 percent of female respondents reporting that calorie counts shaped their dining choices. The reliance on menu labeling also varied by state: in New York, the state with the highest percent of menu label users, 61 percent of individuals reported using calorie counts.

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New York's percentage may be higher than other states due to local requirements in New York City and several New York counties that restaurants display menu item calorie counts. While a 2010 federal law requires restaurants that have at least 20 locations to list calorie information on their menus, regulations to implement the law have still not been finalized, and its enforcement varies based on local laws.

Researchers have struggled to reach a consensus on if posting calorie counts leads to consumers making healthier choices. However, there is evidence that customers who do use calorie information when ordering purchase meals with about 100 to 140 fewer calories than those who do not see or use nutritional information. For some chains, calorie counts can give customers an unpleasant shock, with reveals like the 1,530 calorie Chicken and Spinach Salad at IHOP or the 2,320 calorie Plain Jane Potato at Jason's Deli. However, other restaurants are eager to cash in on customers trying to make healthier choices, such as Burger King with its lower-calorie 'Satisfries' or new fast-casual chains such as Seasons 52, which focuses on providing customers with menu offerings under 500 calories. 

Related: The 500-Calorie Smackdown