According to this wire story, scientists in Norway homed in on epigenetic markers that indicate which stem cells are best suited for regenerating tissue. The catch? The work has been performed on liposuctioned stem cells. As the article points out, "Unlike other sources of adult stem cells, fat is abundant and there is no shortage of donors."
If we're reading this right, the take-home message seems to be that one day your own fat can save you. So abandon that diet and have another donut.