Children who are not treated warmly by their parents are more likely to grow up to be overweight or obese, according to the first-ever study determining the effect of parenting styles on children’s weight.

In an analysis of 10,510 children in England, researchers at Imperial College London found that children with authoritarian or neglectful parents—both types of parenting characterized as lacking warmth—had, on average, a higher weight throughout childhood and adolescence.

The groundbreaking study, which has been peer-reviewed but not yet submitted for publication, suggests parental warmth is the key to a healthy weight, researchers at the International Congress on Obesity, held in Melbourne by the World Obesity Federation, announced on Wednesday.

Childhood obesity is a growing problem in England, with more than a quarter of 4- and 5-year-olds overweight or obese. This figure jumps to 40% for kids ages 10 to 11. Obese children are also five times as likely to be obese adults, and, according to the Harvard School of Public Health, obesity diminishes almost every aspect of health, from reproductive and respiratory function to memory and mood.

Louise Baur, president of the World Obesity Federation, said the study reinforced that “the world today often makes it difficult for children and families to eat well, be physically active, sleep well, and cope with stress.”

Baur added, “Parents who are able to set appropriate limits for their child, while bringing warmth and sensitivity to the relationship, may be better able to help their child be as healthy as possible.”

What’s the best kind of parenting to prevent obesity?

Researchers took data from the Avon Longitudinal Study of Parents and Children—a cohort study of children born in the former county of Avon, England, during 1991 and 1992—and divided parents into four categories based on questionnaires filled in by parents and children: authoritative, authoritarian, permissive, and uninvolved.

Authoritative parents were defined as parents who maintain clear boundaries but were also warm—as opposed to authoritarian parents who maintained strict discipline and showed little warmth. Permissive parents were empathetic but had few rules, and neglectful parents were emotionally uninvolved and placed few rules on their children.

Researchers found that children with parents who were classified as authoritarian or neglectful were more much likely to have a higher weight than those who experienced authoritative parenting, while permissive parenting had little statistical effect on children’s weight.

In a longitudinal look into the data, researchers found that on average a 7-year-old with neglectful or authoritarian parents was on average 1.5 kg (3.3 lbs) heavier than a child with authoritative parents. They also found that these parenting styles affected their children’s weight through early childhood, early adolescence, late adolescence, and early adulthood.

Alexa Segal, study author and researcher at the Centre for Health Economics & Policy Innovation at Imperial College London, explained that authoritarian mothers are characterized by being demanding and controlling while having low warmth and responsiveness, which could lead to their not responding to a child’s hunger cues.

Not allowing a child to select a snack when hungry, or trying to control a child’s food intake by, for example, pressuring him to clean his plate even when he is not hungry, could lead the child to “not develop their own ability to regulate their own energy intake, meaning they might overindulge when they have the ability,” Segal said.

Meanwhile, Segal said, the problem of neglectful parenting may be that when no rules are given the child has free rein to eat as many unhealthy options as are available.

Segal stated this trend can be combated with support classes in which parents learn the importance of parenting style in preventing obesity, and with doctors and other support providers stressing the effects of a lack of parental warmth on a child’s weight.

“The effect of parenting style on a child’s weight is often considered a taboo subject,” Segal noted.

“However, a comprehensive understanding of the associations between parenting style and childhood and adolescent obesity has great potential to inform obesity policy and contribute to the development of more effective health and nutrition programs,” Segal said.