The fat that ages your brain: where it accumulates matters more than how much you weigh

 

It's not just how much you weigh: one study found that fat in the pancreas and the "thin-fat" pattern accelerate brain aging.

For years it has been said that obesity increases the risk of dementia, and several studies show that a high BMI is associated with almost double the risk of developing this type of disease. The new finding is that a study published in Radiology, involving almost 26,000 people from the UK Biobank, shows that it's not just how much fat you have that matters, but  where your body stores it 

Two fat patterns that worry the brain

A team from the Affiliated Hospital of Xuzhou Medical University in China analyzed whole-body MRI scans to measure fat distribution in different compartments, particularly around internal organs. From this data, they identified two unexpected fat distribution profiles with the greatest negative impact on the brain:

1. Elevated pancreatic fat (“pancreatic-predominant”)
   • People with a fat fraction in the pancreas close to 30%, up to several times higher than in other profiles.
   • They tend to have a higher BMI and total fat, but without necessarily showing a noticeable fatty liver, which makes this pattern go unnoticed in clinical practice.
2. “Skinny fat” pattern
   • Individuals who do not appear severely obese based on weight or BMI, but who have a high percentage of body fat, especially in the abdomen, and an unfavorable fat-muscle ratio.
   • In these individuals, the liver and pancreas do not show as much fat, which contributes to this profile being underestimated.

Both patterns were associated with  more gray matter loss, accelerated brain aging, worse cognitive performance, and a higher risk of neurological diseases , in both men and women

Beyond BMI: Why Where Fat Stores Matters

The authors point out that magnetic resonance imaging (MRI) allows doctors to go beyond BMI and see hidden fat in internal organs, such as the pancreas and abdominal viscera. In their daily practice, radiologists often diagnose "fatty liver," but this study suggests that  elevated pancreatic fat could be an even more concerning marker of brain risk  than that of the liver.

The "thin-fat" pattern also sends a key message:  simply "looking thin" is not enough . People with a normal BMI but with a lot of abdominal fat and little muscle mass can exhibit a high-risk metabolic and brain profile. This aligns with previous studies linking abdominal obesity to a higher incidence of dementia, especially in women.

What it means for your health (and what you can do)

The researchers emphasize that the next step will be to understand how these patterns relate to other conditions, such as cardiovascular and metabolic diseases, and how to integrate them into prevention strategies. However, the practical message is already clear:

• Brain health doesn't just depend on "how much you weigh", but  on where your fat accumulates .
• Maintaining a healthy BMI, watching your waistline (abdominal fat), preserving muscle mass, and getting regular checkups is more important than just focusing on the scale.

As the team itself summarizes, "brain health is not just about how much fat you have, but also where it accumulates."