🟠 Moderate Evidence
People with higher skeletal muscle mass and lower visceral fat show biologically younger brain structures on MRI, according to a cross-sectional imaging study of 1,164 healthy adults presented at the Radiological Society of North America annual meeting. The finding suggests that body composition—particularly the ratio of muscle to deep abdominal fat—may be a stronger predictor of brain aging than body weight alone.
Key takeaways
- Higher skeletal muscle mass was associated with biologically younger brain age on MRI imaging
- Visceral fat (deep abdominal fat) showed the strongest association with accelerated brain aging, independent of overall weight
- Subcutaneous fat (fat under the skin) showed no meaningful association with brain aging patterns
Study at a Glance
| Source | Radiological Society of North America |
| Study type | Cross-sectional observational imaging study |
| Sample size | N = 1,164 |
| Population | Healthy adults, average age ~55 years |
| Imaging modality | Whole-body MRI and brain MRI with age estimation |
Body Composition and Brain Age Association
Relationship between muscle, visceral fat, and subcutaneous fat with estimated brain age in 1,164 adults
Source: Meysami et al., presented at Radiological Society of North America, 2025 | Georgian Medical Journal News
Muscle protects the aging brain more than weight loss alone
Researchers at the Radiological Society of North America used advanced MRI analysis to estimate “brain age”—a measure of structural aging in the brain—and correlated it with whole-body composition data in 1,164 healthy middle-aged adults. The team, led by Dr. Somayeh Meysami, found that skeletal muscle mass showed a protective association with younger brain age, while visceral fat (the metabolically active fat that accumulates around organs in the abdomen) was the strongest predictor of accelerated brain aging.
The distinction matters clinically. Visceral fat is known to be metabolically active and linked to chronic inflammation and insulin resistance—both of which are implicated in neurodegenerative processes. By contrast, subcutaneous fat (the fat layer under the skin) showed no meaningful association with brain aging in this cohort, suggesting that location and metabolic activity of fat stores, not total adiposity, may drive brain health outcomes. This finding aligns with research on metabolic aging published in the peer-reviewed literature on visceral adiposity and systemic inflammation.
Body composition reflects metabolic resilience and brain structure
The protective effect of muscle mass likely reflects what researchers term “metabolic resilience”—the capacity of skeletal muscle to regulate glucose, lipid metabolism, and systemic inflammation. Muscle tissue is metabolically active and secretes myokines (muscle-derived signaling molecules) that may support cognitive function and neuroplasticity. Conversely, visceral fat accumulation is associated with a pro-inflammatory state that can cross the blood-brain barrier and accelerate structural changes in the brain.
Dr. Meysami’s team used quantitative brain imaging to estimate biological brain age—a composite measure derived from gray matter volume, white matter integrity, and other structural parameters. In adults with higher muscle mass and lower visceral fat, estimated brain age was younger than chronological age; the reverse was true for those with high visceral fat and low muscle. This suggests that the brain’s structural aging trajectory may be influenced by peripheral metabolic health, specifically the balance between metabolically protective muscle and metabolically harmful visceral fat.
Preserving skeletal muscle mass while reducing visceral fat may be more important for long-term brain health than weight loss alone, according to whole-body MRI data from 1,164 healthy adults.
— Dr. Somayeh Meysami, presented at Radiological Society of North America, 2025
Limitations and clinical implications
This was a cross-sectional observational study, meaning it demonstrates associations between body composition and brain aging but does not prove causation. The researchers did not test interventions (exercise, diet, supplements) in this cohort; rather, they observed natural variation in body composition and correlated it with brain structure. Additionally, all participants were healthy at baseline, so findings may not apply to people with existing neurological disease or severe metabolic dysfunction.
Despite these limitations, the study raises an important reframing for public health messaging about aging and brain health. Rather than focusing solely on body weight or body mass index (BMI)—metrics that do not distinguish between muscle and fat—clinicians and aging adults may benefit from attention to body composition, particularly the preservation of muscle mass and reduction of visceral fat through resistance exercise and metabolic optimization. The results align with emerging evidence that sarcopenia (muscle loss) is linked to cognitive decline, suggesting a bidirectional relationship between muscle and brain aging.
What this means
Frequently asked questions
Is this study proof that muscle protects the brain from aging?
No. This is an observational study that shows associations between body composition and brain structure, not causation. People with more muscle may also exercise more, eat differently, or have other healthy behaviors that protect the brain. A randomized trial testing whether increasing muscle mass slows brain aging would be needed to establish causation.
Does body weight matter at all for brain health?
Body weight (BMI) is a crude measure that conflates muscle and fat. What appears to matter more for brain aging is the composition of that weight—how much is muscle versus visceral fat. Two people of the same weight but different muscle-to-fat ratios may have very different brain aging rates according to this study.
What’s the difference between visceral and subcutaneous fat?
Visceral fat is deep abdominal fat that surrounds organs and is metabolically active, secreting inflammatory molecules. Subcutaneous fat is the layer under the skin and is metabolically inert. This study found visceral fat was linked to brain aging, but subcutaneous fat was not, highlighting the importance of fat location, not just total fat mass.
The study adds weight to a growing body of evidence that clinical approaches to aging should move beyond BMI and consider functional markers like muscle mass and metabolic health. As populations age, identifying modifiable predictors of brain aging—such as muscle preservation—may offer pragmatic targets for intervention and public health strategy. Further prospective and interventional studies are needed to determine whether actively increasing muscle mass and reducing visceral fat through exercise, nutrition, or other means can slow brain aging in real time.
Source: Meysami et al., Radiological Society of North America Annual Meeting, 2025
Was this article helpful?
Disclaimer. This article is health journalism intended for general information and education. It is not medical advice and is not a substitute for professional diagnosis or treatment. Always consult a qualified healthcare provider about your individual circumstances. Full disclaimer →
Related Coverage
Editorial standards. This article was produced under the GMJ News editorial process, with oversight by the GMJ Editorial Board. Our editorial process. Spotted an error? Contact the editorial team.
