Don't assume your weight is OK if the doctor doesn't bring it up.
Patients "should be asking what their BMI is, and tracking that over time," says task force member David Grossman, director for preventive care at the Group Health Cooperative in Seattle.
A normal BMI is less than 25. Obesity begins at 30. In between is considered overweight. To calculate yours: http://www.nhlbisupport.com/bmi/.
The advice sounds like a no-brainer, considering the national anxiety about our growing waistlines. Two-thirds of adults are either overweight or obese. About 17 percent of children and teens are obese, on the road to diabetes, heart disease and other ailments before they're even grown.
Yet BMI remains a mystery for many people. A 2010 survey of members of the American Academy of Family Physicians found that up to 40 percent of those primary-care doctors were computing their patients' BMIs. Surveys show that only about a third of obese patients recall their doctor counseling them about weight loss.
Doctors can struggle with the pounds, too, and Johns Hopkins University researchers recently reported that overweight physicians were less likely to advise their patients about weight loss.
Few doctors are trained to treat obesity; they're discouraged by yo-yo dieting but they don't know what to advise, says Glen Stream, president of the physicians' group.
"The updated recommendation is important because it makes clear exactly what doctors should do to help," he says.
In Monday's Annals of Internal Medicine, the task force concluded that high-intensity behavioral interventions are the best nonsurgical advice for the obese, citing insufficient evidence about lasting effects from weight-loss medications.
Last year, Medicare started paying primary-care doctors for obesity screening and weight-loss counseling for seniors for a year, including weekly meetings for the first month.