Preschoolers who eat dinner with their families, get plenty of rest and don't spend hour after hour in front of the tube appear to be at a significant advantage when it comes to keeping off extra weight.

Independent of diet and exercise, 4-year-olds were 40 percent less likely to be obese if their parents kept them to no more than two hours of TV time daily, if the family ate dinner together at least six nights a week, and if the preschooler slept at least 10 1/2 hours on weekdays, according to a study published in today's issue of the journal Pediatrics.

The best part, experts say, is that such routines are free and relatively easy to accomplish. And if a family can't or won't do all three, one or two will help, said Sarah Anderson, the study's lead author and an assistant professor of epidemiology at Ohio State University's College of Public Health.

Other benefits include improved cognitive and language development and improved social skills, she said.

Her research looked at 8,550 children whose parents were asked about various behaviors in 2005 for the national Early Childhood Longitudinal Study.

Almost 15 percent of the children were exposed to all three routines, and about 12 percent were exposed to none of them. About one in seven children exposed to all three was obese, compared with about one in four of those exposed to none.

Mark Herriott and his wife, Susan McGowan, limit their 3-year-old daughter, Kendall, to no more than an hour of TV a day, which she has to earn by accomplishing chores such as helping set and clear the table.

Kendall sleeps at least 10 1/2 hours a night, usually more, and the Clintonville family values their evening meal together, Herriott said.

None of this was designed expressly to keep Kendall at a healthy weight, he said. The TV choice, for instance, came from the couple's love of books and a desire to nurture that passion in their children.

That said, he's sure that she burns more calories when cartoons aren't on.

"Watching TV, she turns into an inert statue who is just hanging on every word that Dora says. When the TV is off, she is frenetic, she's running around, she's exploring, she's dressing up," Herriott said.

"I think the most important thing about these behaviors is that they don't cost any money. They are equal-opportunity behaviors for all families," said Dr. Matthew Davis, an associate professor of pediatrics, internal medicine and public policy at the University of Michigan.

At a dinner table, portion size is better limited and consumption tends to go down compared with what children eat in front of the television. Sleep improves overall development; those who sleep well -- adults included -- tend to eat less and better. And TV time, as Herriott pointed out, eats away time that could be spent moving around.

"It gives hope to parents, teachers and myself that just changing one thing, one routine can really impact obesity," said Autumn Trombetta, obesity-initiatives program manager for Columbus Public Health.

Family structure is at the core of all three of the contributing factors in the study, noted Dr. Robert Murray, director of Nationwide Children's Hospital's Center for Healthy Weight and Nutrition.

Obese children often have poor structure in their lives, he said.

New parents should think about how they are structuring their child's day, and know that behaviors that start early will shape a child's health as he or she grows, Murray said.

April Scott of Worthington said she's given a lot of thought to what her decisions now will mean for 6-year-old Claudia and 3-year-old Gwyneth as they grow up. She and her husband, David, are strict about TV time and always eat together at the table, she said.

"I didn't have that growing up, and I just want them to have that," she said.

"I want them to learn the appreciation of sitting down and having a meal that was made for you."

mcrane@dispatch.com