Most Thursdays, Chris Berg and his daughters, ages 11 and 8, pack up a meal and drive over to the hospital, where they eat dinner with his wife, who works the night shift.

He says it's all about quality family time. But a five-year study published Monday shows those meals may also protect his girls from developing eating disorders.

The survey of 2,000 Minnesota adolescents found that girls who have five or more meals a week with their families are one-third less likely to develop unhealthy eating habits. That could be anything from skipping meals to abusing diet pills to anorexia.

For reasons experts say are hard to explain, the same is not true of boys. The study by University of Minnesota researchers was published Monday in the Archives of Pediatrics and Adolescent Medicine.

It is the latest in a growing body of evidence showing regular family meals seem to help adolescents avoid a wide variety of health risks, including obesity, drug use, smoking and suicidal thinking. Earlier U of M research has shown that's also true for adolescents who say they don't have the best relationships with their families, but who still eat with them regularly.

The growing research has spurred a movement back to the family dinner -- or breakfast or brunch -- by some busy families, according to a 2006 national survey of adolescents by the National Center on Addiction and Substance Abuse at Columbia University.

"It's hard," said Dianne Neumark-Sztainer, professor of epidemiology at the University of Minnesota and one of the researchers. "You have to make it a priority."

Berg, of Medina, said that's the only way his family makes it work. "It's getting more and more difficult. If you don't plan for it, it won't happen."

In the study published Monday, Neumark-Sztainer went back to a group of nearly 5,000 adolescents from 31 Minnesota schools that she surveyed five years ago about their eating habits. She reconnected with 2,000 of them.

She asked about meals, family relationships, health and how they ate. Not surprisingly, she found that the rate of severe disordered eating increased substantially as the group got older -- from 14.5 percent to nearly 24 percent -- in line with what other research has found. Extreme behavior included self-induced vomiting and abuse of laxatives and diet pills.

"There was a huge increase, especially in diet pill use," she said.

And a majority of girls said they engaged in some kind of less-severe behavior, such as skipping meals, using food substitutes or smoking more instead of eating.

Those high rates are one consequence of the rising incidence of obesity, experts said. "It's easy for kids to get the message that it's OK to do anything possible to lose weight," said Jillian Croll, director of research and education for the Emily Program, a St. Paul-based eating disorder program.

Among the girls who ate five or more meals together with their families, 57.4 percent practiced some kind of unhealthy behavior and 17.4 percent engaged in extreme behaviors. That compared with 64.4 percent and 26 percent, respectively, in the group who said they shared fewer than five family meals a week.

The same protective effect showed up among those who reported binge eating.

Boys are much less likely to suffer from eating disorders, and those in this study were no exception.

"It is pretty striking, the difference between the genders," Neumark-Sztainer said. She said girls may be more sensitive to family relationships.

"And that may come through during the family meals," she said. But there are a whole host of reasons why the families that eat together are healthier.

"You have healthier foods. You have the opportunity for role modeling for parents, more opportunities to connect and more opportunity for parents to monitor for problems," she said.

In fact, family meals may be the only way to pick up on whether kids are developing a disorder, said Joel Jahraus, medical director of the Eating Disorders Institute at Methodist Hospital in St. Louis Park. "Adolescents who develop eating disorders don't want to eat with the family," he said. "They are trying to hide their behavior."

Josephine Marcotty • 612-673-7394