ATLANTA — Next time you go for a checkup, don’t be surprised if your doctor gets on your case about your weight.

The medical profession has issued new guidelines for fighting the nation’s obesity epidemic, and they urge physicians to be a lot more aggressive about helping patients drop those extra pounds.

Doctors should calculate your body mass index, a weight-to-height ratio. And if you need to lose weight, they should come up with a plan and send you for counseling. “We recognize that telling patients to lose weight is not enough,” said Dr. Donna Ryan, co-chair of the guidelines committee.

The good news? By next year, most insurance companies are expected to cover counseling and other obesity treatments, following in the steps of the Medicare program, which began paying for one-on-one help last year. More than a third of U.S. adults are obese. Officials define someone with a BMI of 30 or higher as obese. A 5-foot-9 person would be obese at 203 pounds.

Doctors are well aware that excess weight can trigger diabetes and lead to heart disease and other health problems. Yet surveys have shown that only about a third of obese patients recall their doctor talking to them about their BMI or counseling them about weight loss.

The guidelines were released this week by a group of medical organizations that include the American Heart Association, the American College of Cardiology and the Obesity Society.

Last year, the Food and Drug Administration approved two more obesity-fighting drugs. And this year, the AMA labeled obesity a disease, a measure intended to get doctors to pay more attention to the problem and prod more insurers to pay for treatments.

Yet many people have been on their own when it comes to slimming down, left to sift through the myriad diets and exercise schemes. The guidelines advise doctors to:

At least once year, calculate patients’ BMI, measure their waists and tell them if they are overweight or obese.

Develop a weight-loss plan that includes exercise and moderate calorie-cutting.

Consider recommending weight-loss surgery for patients with a BMI of 40 or for those with a BMI of 35 who also have two other risk factors for heart disease such as diabetes or high blood pressure.

Refer overweight and obese patients who are headed for heart problems to weight-loss programs. Specifically, discuss enrolling them in at least 14 counseling sessions over six months with a registered dietitian, psychologist or other professional with training in weight management.

Diane LeBlanc said the new guidelines are overdue. More than year ago, the Baton Rouge, La., woman sat down with her longtime family doctor to talk about her weight and get a referral for some kind of help. She said the doctor smiled and told her: “There’s a lot of programs out there. But really, you just have to eat less.”

“It just devastated me,” Le- Blanc recalled. “He was saying, ‘It’s all in your mind.’ I was thinking, ‘If I could do that, don’t you think I would have done it by now?’ ”

She changed doctors and has lost 40 pounds from her 5-foot-4 frame since May after getting into an intensive Pennington weight-loss program that includes counseling.