White fat is the kind that makes the battle of the bulge a neverending struggle.
Brown fat is thought to burn calories.
Researchers say we lose brown fat as we age.
Authors of a study in the Cell Metabolism report that they have been able to transform white fat into brown fat and muscle in mice.
The mice gained less weight and showed improved blood sugar levels and insulin tolerance.
The technique is not ready for humans, but scientists say it shows promise as a future treatment for obesity and diabetes.