BAKERSFIELD, Calif. -- Obesity rates in children have more than tripled since the early 1970s. But pediatricians have been reluctant to screen for obesity in children because identifying overweight kids only makes sense if doctors can offer help to correct the problem.

That time has arrived, according to the latest recommendations from the United States Preventive Services Task Force -- a panel of health experts convened by the government to study the issue.

In updated guidelines, the task force concluded that doctors should begin screening for obesity in children age 6 and older.

Screening is simple -- pediatricians calculate a child's body mass index based on his or her height and weight and then compare the numbers for kids of the same age.

Children who are in the top 15 percent are either overweight or obese and should be referred for treatment.

The most effective programs for kids include counseling from dieticians, psychologists, and physical activity experts -- and they must meet at least once a week for one year to achieve the most weight loss.