Obese people may be less intelligent than people who are a healthy weight, a controversial study has found.
Researchers from the University of Manitoba measured Body Mass Index (BMI) and body fat percentages and compared them to the brain structure and function of 32 adults.
They found that overweight and obese people had less white and grey matter in certain key networks of the brain than people of a healthy weight.
The study suggests a lack of white or grey matter can limit connectivity in these networks, which has a negative impact on brain function.
However, the researchers pointed out it is unclear whether people predisposed to obesity are born with this brain structure, or whether weight gain causes it.
The study, published in the journal Frontiers in Neuroscience, says: “Despite the myriad of obesity-related physical and mental health concerns, most overweight individuals struggle to initiate and maintain behaviours that would reduce adiposity and improve their overall health.”
Notably, the researchers found people with a higher BMI and higher fat percentage had less white matter in the salience network of the brain, which is linked to motivation and self-control.
“It stands to reason that these changes could further affect the ability of overweight individuals to exert self-control and maintain healthy lifestyle choices,” co-author Chase Figley said, according to the National Post.
Commenting on the study, Jane deVille-Almond, chair of the British Obesity Society told The Huffington Post there is “bound to be a link with self-control and brain function and obesity but this cannot be equated to intelligence”.
“Plenty of bright intelligent people suffer with weight problems and plenty of people who may be deemed not to be ‘as intelligent’ have a healthy body weight,” she said.
“This study is a small study that does not have any academic significance and can only make the social stigma worse for people who already struggle with their weight.”
Dr Nitin Shori, medical director of the Pharmacy2U Online Doctor service, added: “This research raises a number of sensitive issues and it would be wrong for clinicians to draw any conclusions without much more work being done.
“However, it is certainly true that obesity can have a negative impact on both physical and mental health.”
Dr Shori added that people who are overweight or obese can suffer from low self-esteem and are at increased risk of developing a number of health problems, including high blood pressure, stroke, coronary heart disease and Type 2 diabetes.
“The causes of obesity include poor diet and a lack of exercise. Help, including counselling and medication, is available for anyone who is struggling to control their weight,” he said.
“Anyone who is concerned that their weight is having a detrimental impact on their physical and mental health should seek advice from a GP.”