Brown fat makes you thin

More on "brown fat" — the fat that burns regular fat — from the New Scientist. They say that 50g of brown fat in your body burns 500 calories a day, and hint that it's possible to lipo out your regular white fat and turn it into brown fat and re-implant it.

Brown fat's role in heat generation, also known as thermogenesis, has been extensively studied by animal physiologists. It turns out that brown fat cells have unusual mitochondria, the tiny structures found in almost all cells that release energy from food. In the vast majority of cells this energy is either stored or used to power cellular processes. The mitochondria in brown fat, however, contain a protein called thermogenin (or uncoupling protein 1), which causes energy to dissipate as heat. "This is a tissue whose sole purpose is burning energy," says Francesco Celi, a researcher at the US National Institutes of Health…

Kahn's team is focusing on a compound called bone morphogenetic protein 7, or BMP-7, also known as osteogenic protein 1. It is best known for promoting the formation of bone and cartilage, and a genetically engineered version is used in bone surgery. Last year, the group showed that if cells derived from mouse embryonic stem cells are treated with BMP-7 they turn into brown fat cells. When transplanted into a special breed of mouse that accepts tissue from unrelated individuals, they formed discrete islands of brown fat (Nature, vol 454, p 1000).

To test this approach in people, the team now plans to take white fat cells obtained through liposuction and treat them with BMP-7. The resulting brown fat cells could then be reimplanted into the original donor. "It's got a lot of potential," says Kahn.