By Sarah Klein

MONDAY, Feb. 8, 2010 (Health.com) — Worried about your child’s weight? You can do more than just nag them about eating too much junk food. Implementing three healthy family habits—eating dinner together, making sure they get enough sleep, and limiting TV—may help.

The combination of these three habits is associated with a lower risk of obesity in children, according to a new study.

The study, which included 8,550 4-year-olds from around the United States, found that children who ate dinner with their families more than five times a week, slept for at least 10.5 hours a night, and watched less two hours or less of TV a day were 40% less likely to be obese than children who did none of those things.

Roughly 1 in 7 children who practiced all three of the behaviors was obese, compared to 1 in 4 youngsters who practiced none of them, according to the study, which was published in Pediatrics.

Even maintaining just one of the routines—all of which, on their own, have been linked to a lower risk of childhood obesity in previous studies—lowered the odds that a child would be obese by about 25%, the study found.

“We found an independent effect of each, which suggests that doing more of them was better,” says lead study author Sarah Anderson, PhD, an assistant professor of epidemiology at Ohio State University. “If you were doing one, adding another one—either one—was associated with a lower prevalence of obesity.”

Many families in the study were already implementing at least some of the behaviors. Nearly 40% of the families practiced two of the three, which lowered the odds that a child was obese nearly as much as all three, the researchers found. However, just 15% of families practiced all three of the behaviors, according to the study.

Households were more likely to practice all three if they were white, if they were two-parent families, if the mother wasn't obese, if the mother had a bachelor's degree, or if the household income was higher.

Significantly, however, the study found that the link between the behaviors and the lower risk of obesity held even after they controlled for a family's economic status and other factors, which suggests that the behaviors are beneficial regardless of a family's circumstances.

Next page: Parents should try to adopt these routines

"We should encourage parents to have these routines for young children," says Anderson. "In some families it's going to be harder to do these things [because of] social and economic constraints, but we should consider what would make it possible for them to have these routines in their household."

William T. Dalton III, PhD, an assistant professor of psychology at East Tennessee State University, says that the relationship between the three routines in the study—as well as other factors that weren't studied—is complex, and that they are likely interconnected.

“If children are getting adequate sleep, they’re going to have more energy during the day to be physically active,” says Dalton, who has researched the link between families and obesity but was not involved in the current study. Similarly, he adds, children who eat dinner at the table with their family aren't eating in front of the TV, a bad habit that often leads to less mindful eating and doesn’t teach children how to regulate their food intake.

The larger household context needs to be considered, says Dalton, not just certain behaviors in isolation. "I think it’s important to look at broader family functioning, in terms of how families work as a unit,” he says. "Are the families where children don’t get enough sleep the types of families that have other challenges? [Maybe] both parents are working, so they let the children stay up later because that’s their only chance to see them, and then staying up later leads to more snacking.”

Anderson acknowledges that the study, which used surveys to gauge the frequency of each routine in households, says little about how each household implemented the behaviors. “We don’t know who was eating dinner with the kids, what kind of TV was watched, or how well the child slept,” she says. Nor did she and her co-author assess what kind of food the children ate or how physically active they were.

Anderson and her co-author are unable to say with any certainty that eating dinner together more often, getting more sleep, and watching less TV will help any given child lose weight, because of the other factors that may contribute to a child's obesity (or that may protect normal-weight children from becoming obese).

Still, says Anderson, “We feel comfortable recommending these routines for the prevention of obesity. They may have a potential benefit for obesity, they also have a benefit for children’s development, and they’re not likely to cause the child any harm." Although more research is needed to prove that these routines directly lower childhood obesity, she adds, parents shouldn't wait to implement the behaviors in the study.

Nor, says Dalton, should the routines outlined in the study distract parents from the most important contributors to childhood obesity. In the end, he says, “It still comes down to eating too much and not being active enough.”