Overweight children are less intelligent than their thinner peers, controversial research suggested today.
Scientists in the United States, who followed more than 5,000 children between the ages of nine and 11, found that students with a higher body mass index (BMI) performed worse on tests.
And they were also more likely to have symptoms of depression, the researchers said.
But it’s not clear whether a poor diet harmed brain development or whether an underdeveloped brain caused overeating.
Experts have long warned that a “quick fix environment” that combines unhealthy diets with increasingly sedentary lifestyles has caused problems in the way children develop.
Previous studies have also suggested that BMI is associated with alterations in the development of the brain’s prefrontal cortex. Deficits in working memory can contribute to poor dietary decisions.
Researchers at Washington University in St Louis, Missouri, evaluated data from more than 2,500 girls and 2,700 boys between 2016 and 2018.
During a two-year follow-up, they found that children who scored one point lower on picture and vocabulary tasks had a higher BMI, 0.012 (1.6 percent), on average.
Children classified as overweight or obese (who had a BMI above the 85th percentile) were almost twice as likely to have “more problems annually than those with normal weight,” the scientists said.
writing in the diary JAMA PediatricsThe researchers said the findings highlight the “importance of cognitive and mental health” for weight gain.
They also asked doctors to monitor children who are overweight or obese “for increased problems with depression.”
Future research could explore why this is the case and why some people don’t follow a healthy diet or lifestyle.
Experts have long warned that changes in children’s diets and lack of physical activity have created “the perfect storm” that hinders child development.
Professor Iain Buchan, a public health expert at the University of Liverpool, told MailOnline: “If we look at the change in our energy balance, the way we eat, what we eat, the way we move and interact between us, everything These things have changed dramatically in the last 20 years.
‘Although we are more connected, we are also more sedentary, since everything is done sitting, online or fixed on a device.
‘Our bodies did not evolve to expend so little energy. We need to move and interact physically and spend time unplugged so we can reflect.”
He added: “Life has become very different in terms of pace and food has also changed: we now have unhealthy diets, with junk food rich in fat, salt and sugar that provides quick energy, and that is not good for the health”.
‘We have created a quick-fix environment that focuses on short-term pleasure and causes long-term pain.
“It’s the perfect storm, combined with being fixed in place and the lack of physical interaction: all of these things are causing problems in the way children develop. It’s not what our bodies have evolved to do.
‘These problems have been brewing for a generation and now we are seeing their effects.
“We see an increase in mental health problems, obesity and other diseases, and drug use.”
The pressures of modern life have long been blamed for contributing to what is widely described as a “crisis” in children’s mental health.
More than one million children have had their height and weight measured under the National Child Measurement Program (NCMP). Nationally, the rate among Year 6 children stands at more than a third, despite having fallen slightly since Covid began.
Among sixth-form pupils, national obesity fell from 23.4 per cent in 2021/22 to 22.7 per cent. Meanwhile, the proportion of children considered overweight or obese also decreased, from 37.8 percent to 36.6. Both measures are above pre-pandemic levels
Almost a quarter of children in England currently suffer from a “probable mental disorder”, according to a report from the Office for National Statistics (ONS).
The rate of these disorders, recorded from the responses of a questionnaire to young people between 8 and 16 years old, is increasing.
The 2023 data suggested that 23.3 percent of children had a probable mental disorder, such as anxiety or depression, up from 19 percent the previous year.
Experts have also previously highlighted that the impact of the Covid pandemic and the disruption it caused to children’s education and social lives, along with the cost of living and social media crisis, are damaging children’s mental wellbeing .
The latest data on childhood obesity in England also shows that one in 10 children are too fat when they start primary school, a figure rising to around one in four by Year 6.
Obesity takes a huge financial toll in the UK, with health consequences resulting in lost years of work, care costs and the price of NHS treatment costing the economy an estimated £100k. million per year.
Experts have pointed to a lack of exercise and poor diets high in ultra-processed foods as key factors in the UK’s childhood obesity epidemic.