A new study suggests that your waistline may offer more insight into your brain health than the number on the scale—particularly for older men. When assessing dementia risk, where body fat is stored seems to matter more than how much there is.
New research led by Monash University seeks to clarify conflicting findings from earlier studies on how different aspects of body composition—such as lean mass, fat mass, and abdominal fat—relate to dementia and cognitive decline.
The large-scale study focused on adults aged 65 and older, analyzing data from more than 17,000 participants in Australia and the U.S. who were part of the ASPREE clinical trial and its follow-up. Researchers used the waist circumference-to-BMI ratio as an indicator of abdominal fat, and also examined lean body mass (muscle, bones, organs, and water) and fat mass (total body fat).
Cognitive performance was assessed through tests measuring overall cognition, memory, processing speed, and verbal fluency. Dementia diagnoses were made using strict DSM-IV criteria, based on cognitive evaluations and medical records.
Abdominal Fat Raises Dementia Risk—Especially in Older Men, Study Finds
The study found that a higher waist-to-BMI ratio was associated with a 29% increased overall risk of dementia. Among men, those in the top 25% for abdominal fat had a 46% greater risk of developing dementia compared to those in the lowest 25%—meaning older men with the most belly fat were nearly 1.5 times more likely to develop the condition. These men also experienced faster declines in memory, overall cognitive ability, and mental processing speed. However, abdominal fat didn’t significantly affect verbal fluency.
In contrast, having more lean body mass was consistently linked to a 15% to 38% lower risk of dementia and slower cognitive decline, particularly in areas like memory and processing speed. There were also modest improvements in verbal fluency, especially among men. Interestingly, higher total fat mass was also linked to reduced dementia risk—by as much as 38%—and slower cognitive decline, except in verbal fluency.
Overall, the findings suggest that it’s not just how much fat you have, but where it’s located that matters for brain health.
Centre for Ageing Better/Unsplash
Higher Body Weight May Aid Brain Aging, But Belly Fat Remains a Risk, Especially for Men
“Our findings suggest that higher body weight in older age may help protect against brain aging,” said Professor Joanne Ryan of Monash University. “However, excess belly fat still poses cognitive risks, especially for men.”
She emphasized the importance of maintaining a healthy balance between lean and fat mass, noting that diet and regular exercise are key to brain health in later life.
The study had limitations, including a healthier-than-average sample and estimated body composition data, which may understate risks. Hydration, which can affect these measures, wasn’t tracked.
Still, the results highlight that not all fat is harmful—abdominal fat may be a risk, but overall fat and muscle mass could be protective. Reducing belly fat and preserving muscle through exercise and good nutrition may offer an affordable way to support brain health with age. Always consult a healthcare provider before making major lifestyle changes.
Read the original article on: New Atlas
Read more: Lose fat without losing muscle: A booster of this protein might be the solution
