Yale study reveals hidden cause of childhood obesity—And it’s not just junk food

But preventing childhood obesity is a complex undertaking. While encouraging a healthy diet and adequate exercise have long been two strategies for reducing risk of obesity in children, Yale researchers have recently identified a crucial third: lowering parent stress.

A research team led by Yale psychologist Rajita Sinha has found that reducing parent stress can help prevent childhood obesity in their young children, as per Yale University website.

“It’s the third leg of the stool,” said Sinha. “We already knew that stress can be a big contributor in the development of childhood obesity. The surprise was that when parents handled stress better, their parenting improved, and their young child’s obesity risk went down.”

The new study’s results are published in the journal Pediatrics.

Previous research has shown that parent obesity is a risk factor for childhood obesity, and that parent stress may be an additional hidden driver of early childhood obesity.

Earlier research showed that stressed parents are more likely to rely on fast food and unhealthy eating habits, which can affect children’s behaviour and eating habits. When parents are overwhelmed, family routines may suffer, unhealthy food choices increase, and positive parenting behaviours decline.

But current childhood obesity prevention programs mostly focus on nutrition education and physical activity, which too often fail to produce lasting improvements, said Sinha, the Foundations Fund Professor in Psychiatry and a professor in neuroscience and in child study at Yale School of Medicine.

In the new study, researchers ran a 12-week randomised prevention trial with 114 ethnically and socioeconomically diverse parents with overweight or obese children aged two to five. Parents were assigned to either the parent stress intervention called Parenting Mindfully for Health (PMH), which focused on mindfulness and behavioural self-regulation skills combined with healthy nutrition and physical activity counselling, or to a second, control intervention receiving only healthy nutrition and physical activity counselling.

Both groups met weekly for up to two hours. Parents’ stress and children’s weight was assessed during the 12 weeks, and children’s weight was also measured three months after treatment completed.

In addition, positive parenting behaviours such as parents’ warmth, listening, patience, and positive affect —as well as children’s healthy and unhealthy food intake — were tracked before and after treatment.

At the end, only the PMH group showed lowered parent stress rates, improved positive parenting, and reduced unhealthy eating in children, along with no significant weight gain in their children at three months after treatment.

Parents in the control group did not show similar improvements in parent stress, positive parenting, or unhealthy child food intake, and their children showed significant weight increases — with a six-fold increased risk of moving into the overweight/obesity weight risk group at the three-month follow-up.

Notably, the correlation between high parent stress and reduced positive parenting along with reduced healthy food intake in children remained in the control group after three months but was no longer significant in the PMH group.

“The combination of mindfulness with behavioural self-regulation to manage stress, integrated with healthy nutrition and physical activity, seemed to protect the young children from some of the negative effects of stress on weight gain,” Sinha said.

The new study grew out of ongoing work at the Yale Stress Center, an interdisciplinary consortium launched with the help of a 2007 National Institutes of Health Common Fund program that focuses on the biology of stress, health behaviors, and their impact on chronic mental and physical illnesses.

“Childhood obesity is such a major issue right now, and the results of this study are highly relevant to the current administration’s priority of reducing childhood chronic diseases,” said Sinha. “When people start moving up the weight scale, their risk of obesity-related illnesses, even in children, is increased.”

The study’s findings support the need to evaluate long-term sustained PMH intervention efforts on childhood obesity risk, and two-year outcomes from a larger cohort of families are forthcoming, Sinha said.