Transforming fat cells into calorie-burning machines may sound like a fantasy — 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, and that ability might be harnessed to treat obesity and diabetes, researchers suggest.

Fat is known to help protect animals from the cold, and not only by acting as insulation. In the early 1990s, scientists studying mice discovered that cold temperatures trigger certain fat cells, called brown adipose tissue, to release stored energy in the form of heat — in other words, to burn calories.