Transforming fat cells into calorie-burning machines may sound like the ultimate form of weight control, but the idea is not as far-fetched as it sounds. Unexpectedly, some fat cells directly sense dropping temperatures and release their energy as heat, according to a new study; that ability might be harnessed to treat obesity and diabetes, researchers suggest. Bruce Spiegelman, the Stanley J. Korsmeyer Professor of Cell Biology and Medicine at Dana-Farber Cancer Institute, led the study.