Feel the Burn
Turning on brown fat in humans may boost weight loss
Bruce Spiegelman isn’t always happy with the way his research gets portrayed. He and colleagues discovered a hormone that muscles make during exercise. When given to mice, the hormone causes the animals to burn more energy and lose weight, and improves their response to insulin — all without changing how much the mice eat or exercise. The press touted the discovery as “exercise in a pill.”
“I really hate that,” says Spiegelman, a cell biologist at the Dana-Farber Cancer Institute and Harvard Medical School in Boston. “The goal is not to put exercise in a pill.”
His goal, instead, is to harness a special type of fat, called brown fat for its color, to replicate the metabolic benefits that exercise delivers. While some researchers have dismissed this fat as a mostly obsolete relic that makes little if any contribution to people’s energy expenditure, new research shows that it can make humans feel the energy burn. Some scientists have found chemical secrets for activating brown fat already in the body, while others are learning how to turn energy-storing white fat brown.