Toddlers who have poor relationships with their mother are more likely to pack on extra weight as they grow up, according to a US study.
Researchers who followed nearly 1,000 children into their teens found that more than 25 percent of those who scored lowest on mother-child relationship tests as toddlers went on to become obese at age 15, findings in Pediatrics said.
By contrast, only 13 percent of the children who had a good relationship with their mother became obese.
While that doesn't prove cause and effect, researchers say other work has shown links between children's emotional and intellectual development and how they interact with their mother at a young age.
It's possible that a stressful childhood could make a lasting impression on children's brains, said Sarah Anderson, who worked on the study.
"There is an overlap in the brain between the areas that govern stress and energy balance," said Anderson, at the Ohio State University College of Public Health in Columbus.
"This stress response could be related to obesity through appetite regulation."
The study was based on 977 children who were videotaped while playing with their mother at about one, two and three years of age.
Researchers then assessed the toddler's relationship to their mothers based on the mother's ability to recognize her child's emotional state and respond with warmth, as well as the child's tendency to explore its environment freely, a measure of"attachment security."
A quarter of the toddlers had a "poor-quality" relationship to their mothers, whereas 22 percent achieved perfect scores at each session.
At 15 years, 26 percent of the children with relationship trouble were obese - twice as many as those without such problems.
However, the gap narrowed as more factors were taken into account, including maternal education and household income.
David Gozal, a pediatrician who was not involved in the study, agreed, although he said unhealthy food and a lack of physical activity and sleep are likely to play a bigger role.
Still, stress - both via genetic reprogramming and behavioral changes - may also have an impact, and a poor mother-child relationship could be part of that, he said.
"What you see in adulthood is obviously the cumulative effect of what has happened earlier in life," said Gozal, physician-in-chief at the Corner Children's Hospital in Chicago.
Today, 17 percent of all children and adolescents in the United States are obese, according to the Centers for Disease Control and Prevention.
But Anderson said that even if poor relationships at home contributed, there is no point in chiding mothers.
"Blaming parents is not likely to solve anything. It's important to recognize that there are many competing demands on parents," she added.