Now that it’s time to turn your weight-loss New Year’s resolutions into reality, a healthcare task force that reviewed the effect of diet counseling says extended behavioral counseling can help those at known risk for heart disease and other chronic illnesses.

However, the task force, which was convened by the U.S. Department of Health and Human Services (HHS), said there is insufficient evidence to gauge the effectiveness of brief, routine counseling among healthy adults.

After reviewing diet counseling studies spanning a 35-year period, the U.S. Preventive Services Task Force concluded that intensive diet counseling can help at-risk adult patients eat less fat and more fruits and vegetables. The counseling can be delivered by primary care clinicians or by referral to other specialists, such as nutritionists or dieticians, according to the task force.

Effective counseling for at-risk patients typically involved multiple or group sessions and stressed techniques to boost patients’ skills, motivation, social support and personal involvement in goal-setting, task force members said. Because patients at risk for chronic diseases such as high blood pressure or cholesterol problems may have greater motivation to change their diets, counseling can contribute to positive results, said task force members Michael P. Pignone, M.D. and Alice Ammerman, Ph.D., of the University of North Carolina School of Medicine.

Studies of average-risk patients showed mixed results, but the study did not reveal sufficient evidence of greater health benefits in cases where counseling did improve the patients’ diets, they added.

In addition, most of the evidence on the effectiveness of counseling was derived from patient reports detailing how their eating habits changed, which might not be the most reliable measureof diet change, task force members noted.

Pignone said the task force analyzed 21 different studies in which adult patients were counseled to eat less saturated fat or overall fat; eat more fruits and vegetables; or eat more fiber each day. They ranked the success of the counseling on the overall drop in saturated fat intake or the increase in fruit, vegetable or fiber intake, he said.

Patients who received multiple types of counseling, such as personal evaluations of their diets or group counseling, made bigger changes to their diets than individuals who received less intensive counseling; a combination of interactive materials and brief face-to-face advice also helped patients make larger dietary changes, task force members said.

One of the most important questions that remains is whether small dietary changes can lead to better health, Pignone said. Previous research suggests that moderate or large diet changes are associated with lower rates of heart disease and some types of cancer, he added.