In the first study ever to examine mothers’ and fathers’ parenting styles in relation to the weight of their preschool-aged children, researchers in Australia have found that fathers’ parenting behavior—but not mothers’—was associated with an increased risk in preschool-aged children of being overweight or obese.

The study examined about 5,000 preschoolers, 4 to 5 years old. Data for mothers’ behavior showed no connection to the child’s body mass index, or BMI. However, children of fathers with a “permissive” or “disengaged” parenting style were more likely to be in a higher BMI category. Fathers with an “authoritative” parenting style had children with a lower average BMI.

According to Henry Rodriguez, MD, Associate Professor of Pediatrics and Director of the Pediatric Diabetes Clinical Program at the Indiana University School of Medicine and the James Whitcomb Riley Hospital for Children, this study brings attention to one important way in which behavior contributes to the obesity epidemic.

“It is generally accepted that genetics plays a major role in an individual’s risk for obesity,” Rodriguez says, “but from a population perspective, genetics alone cannot explain the epidemic increase in obesity that we’ve witnessed over the past 10 to 20 years. Genetics don’t change that fast.”

Of the 2,537 boys and 2,446 girls in the study, 15 percent were overweight, and 5 percent were obese. In their report, published in the Dec. ’07 Pediatrics, researchers stated that today, obesity is nearly as prevalent among preschool children as among older children, and kids who are overweight or obese at preschool age tend to remain overweight or obese during their primary school years.

Researchers referred to the widely used Baumrind scale to characterize parental behaviors and styles. Mothers and fathers self-reported, on a continuous scale, their levels of warmth, control, and irritability in their parenting. The levels of these behaviors were ranked based on their answers to certain behavioral questions. For instance, one question researchers used to gauge warmth was “How often do you express affection by hugging, kissing, and holding this child?” Answers could range from 1 to 5, or “never/ almost never” to “all the time.”

Based on their scores, parents were categorized as having authoritative, authoritarian, permissive, or disengaged parenting styles. For instance, a parenting style with high warmth and high control has the best impact on optimal child development, and is classified as an authoritative parent. An authoritarian parent, however, demonstrates high control but low warmth.

While children of authoritative fathers were more likely to have a lower BMI, the odds of being in a higher BMI category increased 59 percent for kids of permissive fathers, and 35 percent for kids of disengaged fathers. Results were analyzed by category for mothers, for fathers, and for mothers and fathers together. Results analyzing the parents separately and together remained consistent in the findings for the father’s role in child BMI. Researchers stated that these results show the significance of the father’s role, the importance of community initiatives to improve parenting, and the possibility for an even greater impact on the BMI of older children due to the same causes observed in the preschoolers.

“A very permissive parent is not likely to set boundaries on eating, and a neglectful parent may prompt the child to seek comfort in eating,” notes Rodriguez.