How obesity affects the brain

Obesity isn’t just harmful to the heart — it can also have a negative effect on the brain.

While we’ve long known about the link between obesity and conditions such as heart disease and diabetes, a growing body of research examining the connection between body fat and the brain’s grey matter reveals that some types of obesity can lead to a greater risk of dementia and stroke.  

For example, a new study  from researchers at the University of South Australia, reported in the Neurobiology of Aging, found that for every extra 3 kilograms of body weight in a person of average height, the amount of gray matter decreased by 0.3%. With the ongoing rise in obesity (globally nearly two million adults are overweight and 650 million have obesity, according to the World Health Organization) this poses big concerns for overall brain health among the obese. 

We know all too well that the obesity problem extends to children — it’s been on the rise over the past 50 years in the pediatric population. Nearly 40 million children younger than five years old and over 340 million young people aged 15–19 years are considered to be overweight or obese. In the U.S., the percentage of children and adolescents with obesity has more than tripled since the 1970s — the prevalence of obesity in those aged 12 to 19 is now 20 percent.

It’s not yet known how obesity affects cognitive functioning in young people — although a small study presented at the Radiographic Society of North America found that MRI scans have found signs of damage in the brains of teens with obesity. It’s thought that obesity may trigger inflammation throughout the body and the nervous system that may affect the brain. 

“Brain changes found in obese adolescents related to important regions responsible for control of appetite, emotions, and cognitive functions,” said Pamela Bertolazzi, the study co-author and a biomedical scientist and PhD student from the University of São Paulo in Brazil.

COVID-19 hasn’t helped. Teens are more sedentary than ever before and this poses a new set of challenges for clinicians trying to assist the pediatric population. 

The message to parents? These are the tried-and-true strategies when it comes to developing healthy eating and exercise habits in young people:  

  • Provide plenty of vegetables, fruits, and whole-grain products.
  • Include low-fat or non-fat milk or dairy products, including cheese and yogurt.
  • Choose lean meats, poultry, fish, lentils, and beans for protein.
  • Encourage your family to drink lots of water.
  • Limit sugary drinks.
  • Limit consumption of sugar and saturated fat.
  • Children ages 3 through 5 years should be active throughout the day. Children and adolescents ages 6 through 17 years should be physically active at least 60 minutes each day. 

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