LITTLE ROCK—About 61 percent of Arkansas school districts ban junk food in school vending machines, up from just 18 percent in 2004, according to a new evaluation of the state’s childhood obesity law.

But the evaluation, released Tuesday by the University of Arkansas for Medical Sciences, also found that 19 percent of schools are ignoring state law and allowing students access to vending machines during the lunch period.

The state in 2003 began measuring students’ body mass indices annually, and set new nutrition and physical activity standards as part of a law, Act 1220.

The effort was championed by then-Gov. Mike Huckabee, who lost more than 100 pounds after being diagnosed with diabetes. Many states adopted similar programs.

“Arkansas’ passage of Act 1220 has put the state in the spotlight nationally, with other states continuing to look to Arkansas as a model for tackling their own obesity problems,” said Dr. Jim Raczynski, dean of the UAMS College of Public Health. “I think the changes in our schools are probably more significant than in other states and that we’re leading the trend nationally and will see continued improvements.”

The evaluation also found that more parents are promoting a healthy atmosphere at home. The report found that 83 percent of families reported limiting family consumption of sweets, chips and soda, compared with 76 percent in 2004.

“This is the first year we’ve seen that both parents and children are making healthier changes in physical activity, what they keep to eat and drink around the house and in the amount of time they allow their children to watch television or play video games,” said Martha Phillips, assistant professor in the UAMS Departments of Psychiatry and Epidemiology. “We’re not just affecting the school environment, but we’re starting to see changes in the home environment, which, if they continue, are very positive signs of changes that complement and support those being made in schools.”

Legislators relaxed the BMI standards last year. Pupils now are measured in kindergarten and in even-numbered grades, with high school juniors and seniors exempt.

The BMI results are released in the fall. Last year, 20.6 percent of schoolchildren tested during the last school year were overweight and 17.2 percent were at risk for being overweight. The figures are about the same as the year before.