Texas fourth-graders were overweight at a rate 46 percent higher than children of similar age elsewhere in the country, said Deanna Hoelscher, principal investigator of study, conducted by the University of Texas School of Public Health.

"Parents do need to watch this in their kids," she said. "What this means is being overweight is a health risk for kids. Parents need to look at that as something they need to take some measures to prevent."

Researchers collected data from more than 6,000 students in 30 schools districts and 132 schools throughout Texas from 1999 to 2001. Hoelscher said the study is one of the first to gather statewide data based on measured height and weight of elementary and secondary students.

Obesity is defined by a formula involving height and weight, called the body mass index, or BMI. A BMI of 18 to 25 is considered healthy. People with a BMI over 25 are considered overweight and those whose BMI is 30 or more are classified as obese.

The Texas study, which will be published in next month's American Journal of Public Health, found 22 percent of fourth-graders, 19 percent of eighth-graders and nearly 16 percent of 11th-graders were overweight. Data from the study's first year was released Thursday.

Hoelscher said national figures aren't broken up by specific school grades but the most recent ones show 15.3 percent of children ages 6 to 11 were overweight, while 15.5 percent of kids ages 12 to 19 were carrying extra pounds.

The federal government has set as a goal of having only 5 percent of school-aged children classified as overweight by 2010.

"We're not close to that," said Hoelscher, who is also director of the public health school's human nutrition center.

Marilyn Tanner, a clinical pediatric dietitian at the Washington University School of Medicine in St. Louis, said the number of obese children across the country has increased tremendously in the last 15 years and they keep getting younger.

"Now it's at epidemic proportions," said Tanner, who also is a spokeswoman for the American Dietetic Association. "I've had 2- and 3-year-olds come in."

The percentage of overweight students in Texas was much higher among minorities, Hoelscher said.

For Hispanic boys in all grade levels, Hispanic girls in fourth-grade and black girls in the fourth- and eighth-grades, the percentage of overweight children ranged from 23 percent to nearly 33 percent. That's five to six times higher than national recommendations.

Hoelscher said she has no definitive answers for why Texas children are more overweight.

Cultural differences in food choices, body image and exercise could be possible reasons why minority children have higher rates of being overweight, Tanner said.