In a mice experiment, the amount of brown fat cells in older mice was maintained at almost the level equivalent to that of younger mice. (ahealthblog.com)
As brown fat cells burn stored fat, the more of them you have, the more calories you burn overall. (liveinthenow.com)
However, he points out, many hurdles remain, including the fact that human fatty tissue has few brown fat cells. (sciencemag.org)