Born thin? Slim chance.
While some people agonize over tracking every calorie to maintain their figures, others seem to have won the genetic lottery with a naturally speedy metabolism — and all the health benefits that come with it.
Now, scientists have found a specific “skinny gene” mutation that’s keeping about one in 7,000 people naturally svelte.
And if you’re thinking, “Well, isn’t that just so nice for them?” — this research could open the door to another kind of drug therapy that could one day reproduce the effects in the rest of us.
Publishing in the journal Nature, researchers at looked at genetic data from over a million people across three continents to see if there were any mutations that influenced metabolism, or how our bodies convert food to energy.
They found our FNIP1 gene plays a role. We evolved this gene to slow down calorie burning when food is plentiful, storing it to survive food scarcity down the road.
When it’s turned off, it burns calories faster rather than storing them for use later. And people with this mutation have their FNIP1 genes turned off.
“Nowadays, we are living in a very calorie-rich environment, and historically there’s no precedent for this,” Luca Lotta, a senior author on the study, told Scientific American. “These incredibly rare mutations, which might have been unfavorable for many millennia, are now favorable to the body.”
We get two copies of the gene — one from each parent — and about 150 people examined had one copy turned off.
These lucky few had lower weight, body fat and liver fat — and also developed more lean muscle.
There are some other serious health upsides, including lower cholesterol, with a drastically decreased risk for a slew of conditions. These include heart attack, stroke, kidney disease and non-alcoholic fatty liver disease.
Why not turn off both copies? That can cause major issues, as they help cells direct energy use and play a critical role in the immune system. It could also affect the heart.
A possible drug in the future
Researchers in the study also looked at mice to see if they could increase their metabolism by turning off a copy of FNIP1.
They found these mice were protected against weight and fat gain and had more lean muscle. They also had more sensitivity to insulin (reducing risk of diabetes) and lower fat in the liver.
This shows some promise, though researchers note it’s unclear whether this is safe to try in humans at this point. Any therapy would be “many years away,” Lotta said.
Gene reprogramming has shown some promise for weight loss — but still only in mice. In 2025, researchers tried a one-time injection to change GLP-1 production in the body, hoping to provide an alternative to repeated injections and bad side effects from the traditional jab.
But with drugs like traditional GLP-1s (Ozempic, Wegovy), patients can stop if dangerous side effects appear. Gene therapy is more permanent.
