Girls who regularly dine with their families are less likely to develop eating disorders or resort to extreme weight control measures, according to a new study.

Schoolgirls who ate five or more meals a week with their families had just two-thirds the odds of engaging in extreme weight control behavior such as diuretics, diet pills, laxatives or self-induced vomiting five years later, according to a study in the Archives of Pediatrics & Adolescent Medicine. Mealtime habits made little difference among boys, researchers found.

More than half of teenage girls and almost a third of teenage boys in the U.S. use unhealthful measures to control weight, including skipping meals, fasting, smoking cigarettes, vomiting and taking laxatives, according to the National Eating Disorders Association. Americans spend more than $40 billion on dieting and diet products each year, the association estimates.

"Findings suggest that regular family meals during adolescence can play a protective role for extreme weight control behaviors in adolescent girls but not boys," researchers said. "It is important to help families find more ways to increase the frequency of family meals."

Researchers, led by Dianne Neumark-Sztainer at the University of Minnesota School of Public Health, surveyed 2,516 adolescents in 31 Minnesota schools in 1999 about their family meal habits, interactions, eating behaviors and body mass index. A follow up survey in 2004 was completed by 53 percent of the original group.

The study found overall prevalence of extreme weight control behaviors, including self-induced vomiting and use of laxatives, diet pills or diuretics, rose to 23.9 percent in the 2004 survey, from 14.5 percent five years earlier. Girls who regularly dined with family were "significantly" less likely to develop disorders as they grew older.

"The idea is to spend some time together as a family around a table," Neumark-Sztainer said in a phone interview. "Families need to think differently about how to make family meals happen, whether it's both parents being involved, making use of convenience foods, getting children involved in preparation, or spending some meals in restaurants."

By re-examining habits five years after the mealtime survey, the study limits the impact of girls who may have avoided family meals to hide eating disorders, Neumark-Sztainer said.

The study didn't explain why boys had different results. Researchers speculated that girls were more involved in food preparation and got more benefit from closer family interaction, while boys who ate regularly at home may be "different in some way that increases their risk for disordered eating behaviors."