Your calorie budget: you probably are busting it

Quick: how many calories have you eaten today, how many should you eat — and how many are in that burrito you're eyeing?

If you don't know, you are not alone. When it comes to knowing and sticking to a daily calorie budget, most people have a lot to learn. A few examples:

• When researchers from Duke University stood outside a Chipotle restaurant and asked patrons to estimate the calories in their burritos, the average guess was 630. Actual average: 900.

• Registered dietitians did not do much better in a test conducted by the Center for Science in the Public Interest (CSPI): Given a plate of restaurant food, even the pros underestimated calories by 200 to 600 calories.

• In an attempt to see if people knew roughly how many calories they should eat, researchers at Johns Hopkins University surveyed 246 regulars in their hospital cafeteria and found 58% were not aware of the ballpark 2000-calorie target for adults.

The hospital test included doctors, nurses and other health professionals, and "if they don't know, it's probably worse in the general population," says Lawrence Cheskin, who directs a weight management center there.

Cheskin's study successfully used weekly text reminders to teach the 2000-calorie-a-day standard to participants.

But it may be time for a broader effort to teach the entire nation about calorie counts, says Margo Wootan, director of nutrition policy at CSPI.

"There are women who have been dieting on and off their whole lives and know calories very well," Wootan says. "Most of the general public doesn't."

Heather Mangieri, a registered dietitian in Pittsburgh, says: "Many consumers know too many calories can lead to weight gain, but not much more than that." When most people do think about the calories they eat, they underestimate, says Mangieri, a spokesperson for the Academy of Nutrition and Dietetics, a professional group.

The public soon is likely to get more calorie information from at least a couple of sources: chain restaurants and food labels.

Under a provision of the Affordable Care Act, chains with more than 20 locations will need to list calorie counts on menus and sign boards. The Food and Drug Administration has finished writing the rules, and once the White House releases them, chains will get at least a few months to comply, Wootan says. Some restaurants are listing calories already, partly in response to state and local laws.

Under additional proposed rules still under FDA review, calorie numbers on packaged food labels would be bigger, bolder and based on more realistic serving sizes.

It's not clear how many people will notice or use the new information, but those who do are going to need some context. Otherwise, "if you see a 2000-calorie entrée at a restaurant, you don't know how much of an impact that is going to have," Wootan says.

So, how many calories do you need? The 2000-calorie-a-day standard is just a ballpark figure, used by FDA to calculate daily values on food labels. It will be printed on menus as well, Wootan says. But actual needs vary by gender, age, size and activity levels.

Here are the typical calorie needs of inactive adults, according to the U.S. Department of Agriculture:

WOMEN

• Ages 19-30: 2,000 calories

• 31-50: 1,800 calories

• 51-plus: 1,600 calories

MEN

• Ages 19-30: 2,400 calories

• 31-50: 2,200 calories

• 51-plus: 2,000 calories

People who are more active need more calories. Taller, heavier people need more than shorter, lighter people. Calculators that use those factors to show how many calories you need to maintain your current weight are available online, including at MayoClinc.org.

Even those counts may be off if you have an unusually slow or fast-burning metabolism. A doctor can give you a breath test to check that and help you set a more individualized calorie budget, Cheskin says.

Of course, a majority of adults in the United States want to lose weight. For that, there is a one-size-fits-all calorie formula, Cheskin says: Cut 500 calories a day (the amount in one large McDonald's' Mocha drink) and you will lose about a pound a week, assuming you don't change your activity level.

Despite the always-raging debate about which diets work best, Mangieri says, the laws of nature still apply: "If your calories in are less than your energy expended, it should result in weight loss."