Keeping your weight in check could protect your brain from damage


By Ed Pinches | Thursday 28 January 2021

Scientists from the University of Sheffield have found that obesity is linked with poorer brain health in people with and without memory and thinking problems. The research is published in the Journal of Alzheimer’s Disease Reports.

What did the researchers do?

Researchers collected brain scans from 47 volunteers diagnosed with mild Alzheimer’s disease, 68 with mild cognitive impairment (MCI), and 57 cognitively healthy people. They looked at these scans for key markers of brain health.

The scientists also calculated people’s body mass index (BMI). BMI is used to measure a person’s size relative to their height. It is commonly used by doctors to help assess whether a person is a healthy weight or obese. In the UK, a BMI score above 25 may indicate that a person is overweight, whereas a score of below 18.5 may suggest that a person is underweight. The researchers also measured people’s waist sizes.

What did the scientists find?

They found in cognitively healthy individuals’ and in those with early-stage memory problems or mild cognitive impairment, obesity was linked with reduced brain structure and reduced blood flow.

The researchers think being overweight or obese could contribute to brains becoming more vulnerable to disease in people with no or early-stage memory problems. They also suggest that in people with mild Alzheimer’s disease, maintaining a higher body weight within the normal range and with better nutrition could help preserve brain health.

Our expert reaction

Dr James Connell from Alzheimer’s Research UK said:
“Obesity is a risk factor for dementia and this study is further evidence that keeping our weight in check helps keep our brains healthy as we age. While BMI can be a crude measure and not necessarily a good indication of our general health, limiting the amount of body fat we carry is important for body and brain alike.

“This study cannot show how body mass and fat can impact disease onset and further research is needed to look at how obesity might cause dementia. The good news is that while there is no sure-fire way to prevent dementia, research suggests that 40% of cases could be down to factors that we may be able to influence.

“We must do all we can to help reduce the number of people who will go on to develop dementia in future. That’s why Alzheimer’s Research UK has launched the Think Brain Health campaign as an important first step.

“As well as maintaining a healthy weight, the best evidence suggests that staying mentally and physically active, not smoking, only drinking in moderation, eating a healthy diet, and keeping blood pressure and cholesterol in check can help us to keep our dementia risk as low as possible.”

To find out more about how people can support a healthy brain visit


By submitting a comment you agree to our comments policy.
Please do not post any personal information about yourself or anyone else, especially any health data or other sensitive data. If you do submit sensitive data, you consent to us handling it in line with our comments policy.

Leave a Comment

About the author

Ed Pinches