Can parents' attitudes during pregnancy influence whether their children will be overweight? Researchers from Emory University in Atlanta and the University of Bristol in England revealed there may be an association between the two.

The collaborative study titled "The relationship between parental locus of control and adolescent obesity: a longitudinal pre-birth cohort" was published in the International Journal of Obesity.

The study explored an aspect of psychology known as the locus of control or LOC. An internal LOC indicates that a person believes that they can influence outcomes (such as health) through their actions. On the other hand, a person with an external LOC believes that luck and circumstance play bigger roles.

"Although we know that poor diet and lack of exercise are partly responsible for increasing obesity in both adults and children in the developed world, there is little research into the contribution of psychological factors behind excessive weight gain," said lead author Jean Golding, who founded the Children of the 90s study.

Over 7000 parents from south-west England participated in the aforementioned study, answering questions about their personality, mood, and attitude during pregnancy. Similar data from their children (including fat mass measurement up to the age of 17) were also obtained.

The research team found an association between parents with an external LOC and an increased fat mass in their teenage offspring. At the age of 15, teenagers had 1.7 kilograms of excess fat mass in their body if their mothers had an external LOC when measured during pregnancy. If their fathers had an external LOC, the teenager had an excess fat mass of 1.49 kilograms. 

"[We have] been able to show that a lack of self-belief in a parent's ability to influence change by healthy eating, stopping smoking or breastfeeding is a contributing factor to their child being overweight by the time they are 15," said Golding. She believed the findings were of significance for health campaigners who hope to change behavior.

Research has shown that obesity rates among children and adolescents are on the rise around the world. According to the Centers for Disease Control and Prevention, the percentage of this age group affected by obesity is more than three times higher today than it was during the 1970s.

To gain a better understanding, future research may explore the differences between parents who managed to change their LOC compared to those who did not change. The team also hoped to study other factors such as parental educational attainment and sleeping habits.

"We see this as an initial step in understanding the complex effects of parents' locus of control on their children's ability to develop a healthy style during the, at times, tumultuous teenage years," said co-author Stephen Nowicki, a professor of psychology at Emory University.