Fiction. A new study by researchers in the United Kingdom tracked children from age 11 through age 16, measuring their weight, body fat and waist circumference. The researchers found that children who were overweight at 11 were likely to still be overweight five years later.

The study also found that obesity in early adolescence was a strong sign of persistent obesity. Few children who were obese at age 11 were able to achieve a healthy weight by age 16. Waist circumference over the course of the study increased by an average of about 1 inch.

Over the past 20 years, the obesity rates among children in the United States and the U.K. have both tripled. But the study, published this month by the British Medical Journal, suggests the problem may be starting earlier than previously believed. The researchers suggested that efforts to combat rising obesity rates might have to target children at a much younger age.

Over the study period, between 17 percent and 19 percent of children were classified as overweight and 5.5 percent to 6.9 percent as obese. More girls than boys had unhealthy weights, and weights were higher among children in lower-income families. Black girls weighed more on average than did white or Asian girls, but there were no significant differences along racial lines among boys.

While 7 percent of overweight or obese children moved into the healthy weight range, an equal percentage moved from healthy weight to the overweight or obese category.

”The results of this study give cause for concern,” the authors wrote. ”Children who are obese when they enter secondary school will likely leave it obese.”

The study findings also showed that obesity rates are rising over time. In 1997, a similar study found an average body mass index among 12 year olds was 18.5 for boys and 19.2 for girls. By 2002, those averages had risen to 19.4 for boys and 20.0 for girls.

The data also showed a continued increase in waist circumferences, increasing the risk for metabolic syndrome among children. Metabolic syndrome is a precursor to heart disease defined by having several risk factors including abdominal obesity, high cholesterol levels, high blood pressure and insulin resistance. A previous study found that about one in eight school-aged children have three or more risk factors of metabolic syndrome.

– Markian Hawryluk