The surprising MRI pattern researchers say might keep your brain biologically younger
A new MRI study presented at the Radiological Society of North America finds something unexpected: your muscle-to-visceral-fat ratio may predict how old your brain looks.
🧠 Researchers at Washington University report that people with more muscle and less hidden belly fat show younger-looking brains, even when they’re the same age on paper.
Key Takeaways
- Higher visceral fat-to-muscle ratio was linked to older-appearing brains
- Subcutaneous fat showed no link to brain aging
- Muscle appears to support healthier metabolic and anti-inflammatory signaling
- Hidden belly fat is strongly tied to inflammation and vascular stress
- Findings may influence future use of GLP-1 weight-loss drugs, which can reduce muscle
The Most Interesting Finding
The MRI scans revealed a clear pattern: people with more muscle had younger-looking brains, and those with more visceral fat had older-looking brains. This connection held even after adjusting for age.
Subcutaneous fat, the kind you can pinch, didn’t matter. It was the hidden fat deep in the abdomen that predicted brain aging markers, along with how much muscle people carried.
Visceral fat is metabolically active and deeply inflammatory, which appears to accelerate brain aging.
Why This Matters
Visceral fat drives inflammation, metabolic dysfunction, and unhealthy cholesterol levels. These processes increase cerebrovascular stress and may promote toxic proteins like amyloid and tau.
Muscle does the opposite. It helps regulate glucose, improves mitochondrial efficiency, and releases anti-inflammatory molecules that protect tissues.
This makes muscle one of the few modifiable levers we have for long-term brain resilience.
If this holds up in larger studies, body composition could matter more than weight for dementia prevention.
What the Researchers Actually Did
The team analyzed whole-body and brain MRIs from 1,164 adults, average age around 55. The fat-versus-muscle contrast on MRI allowed precise measurement of visceral fat, subcutaneous fat, and muscle volume.
They then used a brain-age prediction model, which estimates biological brain age based on structural MRI features.
When they compared these brain-age estimates with body composition, the strongest link was clear:
higher visceral fat-to-muscle ratio = older predicted brain age.
This was consistent across four different study sites.
What the Findings Suggest
- Hidden belly fat might be accelerating structural brain aging
- Muscle mass might buffer the brain through improved metabolic and anti-inflammatory health
- Traditional measures like BMI may miss crucial risk patterns
- Muscle-preserving weight loss may become a major focus of dementia-prevention research
📉 Early evidence suggests that a higher muscle-to-visceral-fat ratio could be a protective body-type signature.
The GLP-1 Question
The results raise an important real-world concern. Popular weight-loss medications such as Ozempic and Mounjaro can reduce muscle along with fat.
If muscle plays a protective role in brain aging, future drug protocols might need to prioritize muscle retention or combine medication with resistance training.
Dr. Cyrus Raji notes that future therapies may be designed to reduce fat while preserving or expanding muscle volume.
What We Still Don’t Know
These data were presented at a conference, not yet peer-reviewed.
They also cannot prove causality. Lifestyle, genetics, and metabolic factors could influence both muscle levels and brain aging.
Whether GLP-1 medications directly influence brain-age markers is also unknown.
Real-Life Takeaways You Can Use
💪 Add or preserve muscle
Strength training, higher protein intake, and maintaining movement throughout the day all help build muscle, which appears to support healthier brain aging.
🔥 Reduce visceral fat specifically
This responds best to strength training, high-intensity intervals, better sleep, and improved metabolic health.
📏 Ignore the scale
A person with stable weight but more muscle and less visceral fat may have a significantly “younger” brain.
A Muscle-Protective Routine
Three weekly habits shown to support muscle and reduce visceral fat:
- Strength training 2 to 3 times per week
Large compound movements appear most effective. - 30 to 45 minutes of brisk walking daily
Linked to lower visceral fat and better insulin sensitivity. - 25 to 35 grams of protein per meal
Supports muscle protein synthesis, especially in midlife adults.
Sources
- Radiological Society of North America (RSNA). More Muscle, Less Belly Fat Slows Brain Aging.
Press Release, 2025. https://www.rsna.org/media/press/2025/2614
