Hi Catando,
I'm no expert on fat-cells, but I think I read in a book about loosing weight, that you can only decrease the size of the fat-cells and not the number of fat-cells. But when gaining extreme amounts of weight you can increase the number of fat cells.
This seems to be a very mean
one way function. And that is why people who once were very obese have a harder time keeping their weight under control than people who were always slim, because they have so many fat-cells that scream for more food than the slender guys.
But that is just what I read.