You probably know the shiver that hits you when you step outside on a cold morning. Most of us just want it to stop. But the body has a built-in way to warm itself up from the inside, using a special kind of fat.
A new paper in Nature, published on October 14, 2026, reports that people whose bodies carry active "brown fat" tend to have better heart and blood sugar health. They also have lower rates of anxiety and depression.
That mental health link is the surprise. Brown fat has been studied for years mainly as a calorie burner.
The team, from Weill Cornell Medicine, Rockefeller University and Memorial Sloan Kettering Cancer Center, say this is the first time it has been tied to psychiatric illness in a large patient dataset.
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How the researchers spotted the mental health link
The team looked at more than 100,000 PET/CT scans taken for cancer surveillance. These scans happen to light up brown fat when it is active, in areas like the neck, the armpits and around the heart and kidneys.
Then they matched the scans against more than 500 health conditions in the patients' records. People with detectable brown fat had lower rates of type 2 diabetes and heart disease, as earlier work had suggested. They also had fewer diagnoses of anxiety and depression.
The researchers do not claim brown fat directly protects the mind.
Dr. Nicolás Gómez-Banoy, the paper's first author at Weill Cornell Medicine, offered a theory. "We know that metabolically healthy people tend to have a lower incidence of psychiatric diseases, so it could be that having brown fat makes you more metabolically healthy," he said.
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Patients taking SSRIs, a common type of antidepressant, tended to show less brown fat activity on their scans. That is an association, not proof the drugs reduce it.
A blood pressure pill that nudges brown fat awake
The second half of the story is about losartan, a long-approved blood pressure drug that works by blocking a hormone called angiotensin.
In cell experiments and in mice, losartan directly ramped up activity in brown fat and raised the amount of energy the body burned.
Gómez-Banoy noted that losartan's blood pressure effect and its brown fat effect appear to run through separate molecular pathways.
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In plain terms, that means a future drug might be designed to keep the brown fat benefit without lowering blood pressure in people who do not need that.
This is not a reason to start or stop any medication. The researchers tested losartan in a lab dish and in animals in this part of the work. A human trial of the metabolic effect has not been run.
What any reader can do today
You cannot pop a pill to activate brown fat, but the body has a free switch for it, and that switch is cold.
In a classic study in the New England Journal of Medicine from 2009, brown fat lit up in 23 of 24 healthy adults after two hours in a cool room near 60 degrees Fahrenheit. It stayed quiet when the same people were kept warm.
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This article is made and published by Aksel Kryhlmand, who may have used AI in the preparation.