WASHINGTON — More than half of Americans say they already have enough information at restaurants to decide whether they are making a healthy purchase. But they want even more.

According to an Associated Press-GfK poll conducted in December, most Americans favor labeling calories on menus in fast food and sit-down restaurants. Most favor labels for prepared foods in the grocery store, too.

The poll was conducted a little more than a week after the Food and Drug Administration announced new rules will require restaurants and other establishments that sell prepared foods and have 20 or more locations to post the calorie content of food “clearly and conspicuously” on their menus, menu boards and displays. Companies will have until November 2015 to comply.

A majority of Americans — 56 percent — favor requiring fast food restaurants to post calorie amounts on menus, while 54 percent favor the calorie postings at sit-down restaurants and 52 percent favor the labels at prepared food counters at grocery stores.Slightly fewer approved of requiring the calorie postings in other dining locations.Forty-nine percent of Americans supported posting calories on coffee shop menus and 44 percent approved of the postings on vending machines and at movie theaters.

Women are more likely than men to say they favor labeling requirements at restaurants and prepared-food counters, though a majority of men support the labeling at fast food restaurants and around half support it at sit-down restaurants.College-educated respondents are more likely than those without a college education to favor labeling requirements at all of the establishments.The support appears to be relatively bipartisan. Democrats are significantly more likely to support the calorie postings than independents or Republicans, but a slim majority of Republicans still support calorie postings.

The idea behind the rules is that people may pass on that bacon double cheeseburger if they know it has hundreds of calories — and, in turn, restaurants may make their foods healthier to keep calorie counts down. The menus and menu boards will tell diners that a 2,000-calorie diet is used as the basis for daily nutrition, noting that individual calorie needs may vary. Additional nutritional information beyond calories, including sodium, fats, sugar and other items, must be available upon request.When they're judging whether a food item is a healthy choice or not, 55 percent of Americans say how many calories it contains is very or extremely important to them. Same with sodium levels.Sugar and fat were slightly more important to health-conscious diners — 61 percent said sugar was very or extremely important when deciding on healthy purchases and 59 percent said the same about the amount of fat.