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Counseling about diet and exercise provides a positive but small effect in preventing cardiovascular disease for otherwise-healthy adults, according to a new recommendation from one of the nation’s most influential health-care organizations.

The U.S. Preventive Services Task Force, which makes recommendations that are often followed by clinicians and insurers, released an updated guideline July 11 on one of the nation’s most pressing problems: the obesity epidemic that is estimated to affect 1 in 3 adults.

After reviewing the results of 88 clinical trials, the independent panel of experts maintained a middle-of-the-road C grade for diet and exercise counseling for normal-weight and overweight people with no known risk factors for heart disease such as hypertension, high blood sugar levels, elevated blood cholesterol or diabetes. The rating leaves it up to individual doctors to decide which patients might benefit from more-intensive weight-loss programs often led by nutritionists who offer advice and regular checkups one-on-one and in group settings.

This higher-level attention, often delivered through six-month “comprehensive lifestyle” programs, is already strongly recommended for anyone with cardiovascular risk factors and for those whose body mass index classifies them as obese. Studies have shown clear and substantial benefits for such people. For example, diabetic patients are sometimes able to stop taking medications after moving toward healthier food choices and becoming more active.

But after looking at the evidence related to overweight and normal-weight people, experts were not able to find that behavioral counseling made a huge difference in who ended up developing heart disease.

The C rating is important for another reason: The Affordable Care Act requires all health insurers to cover preventive services receiving an A or B rating from the task force. So while insurance companies are required to cover weight-loss counseling for those who are obese, that is not the case for those who are merely overweight — even though the American Heart Association recommends such counseling for people in both weight categories.

Carol Mangione, a task force member and internal medicine specialist who teaches at the UCLA David Geffen School of Medicine, said the letter grade should not be taken as evidence that diet and exercise changes are not beneficial or critical in fighting obesity. It’s just that other actions, such as quitting smoking, deliver a larger benefit and thus get a higher grade.

As for the meaning of a C grade under the Affordable Care Act? That’s not part of the evaluation process.

“We look at the clinical evidence, but we don’t consider insurance coverage at all,” Mangione said.

Because it looks at weight through the lens of cardiovascular disease, the recommendation is far from the last word on who should be told to enroll in a comprehensive lifestyle program, said James Sallis, a well-known behavioral medicine researcher at the University of California at San Diego.

“The problem is, diet and exercise specifically are related to many different diseases,” Sallis said. “Cardiologists don’t pay much attention to cancer and osteoporosis and depression, but they are all affected by obesity. Recently, as an example, there was a very large study that linked physical activity levels to 13 different cancers.”

The bigger problem, he added, is that doctors often don’t know what to do when they encounter people who are overweight and at risk of becoming obese. Often, he said, they send such patients to gyms and other self-directed resources even though evidence shows that the best results are obtained from programs that help people set specific goals, have accurate ways to track progress and have a mechanism, such as group meetings where results are shared, to provide accountability.

Creating a link between doctors and these options, he said, may be necessary to reverse the obesity epidemic, and that’s why the C grade was a little disappointing.

“A C recommendation is not going to stimulate much change. The way our system works, if they don’t have a diagnosis that would lead to coverage, then they are going to have to pay out-of-pocket. When patients have to pay out-of-pocket, they’re less likely to follow a doctor’s recommendations,” Sallis said.

— San Diego Union-Tribune