Children in an intensive obesity program that included exercise and coaching on health and nutrition for their parents were able to slim down and keep weight off a year after the program ended, a U.S. study said.

Obesity programs aimed at youth have generally not shown much long-term success, both in keeping children involved during the program and still motivated afterwards.

A team led by Mary Savoye of Yale University signed up about 200 children aged 8 to 16 for one of two programs. All were in the highest 5 percent for their age and gender for body mass index (BMI), a measure of weight for height, were mostly low-income, and were from mixed ethnic backgrounds.

The children were randomly assigned to either the less intensive program, which consisted of counseling appointments led by social workers, doctors and dieticians, once every six months.

Those in the intensive program took part in aerobic exercise sessions twice a week and had classes in nutrition and healthy behavior once a week for the first six months. For the next six months, sessions went down to twice a month.

Parents were also coached about health and nutrition. "This study, unprecedented because of the high degree of obesity and ethnically diverse backgrounds of the children, reveals that benefits of an intensive lifestyle program can be sustained 12 months after completing the active intervention phase," Savoye and her colleagues said in Pediatrics.

At several points - after 6 months of the intensive program, then 12 months, then a year after its end - Savoye and her team measured the participants' BMI, percent of body fat, blood pressure, insulin resistance, and total cholesterol.

Six months into the intensive program, children had lost an average of about 5 pounds (2.3 kg). After 12 months, they had gained about 1 pound, while another year after the intensive program had ended they were up 13 pounds from the start - but their BMI was lower because they were growing at the same time.

They also had healthier cholesterol levels.

In contrast, children in the twice-a-year counseling group gained 10 pounds on average in the first 6 months, 18 pounds after a year, and 26 pounds after 2 years, which all equaled increases in BMI.

One of the difficulties was that more than half of the children in both groups didn't complete the study, which Savoye said was not unusual for obesity interventions for youth.

But she added that the program could be used with other groups of children, possibly even more successfully.

"If this worked on this most challenging population, it can work really in any population that you put it in," she said.