Fat Cells are Replaced Throughout Life

It is known that every adult has a relatively constant number of fat cells - obese people just tend to have more of them than thin people. When we gain or lose weight our fat cells swell or shrink, but the number of fat cells stays the same. This is one reason why it is so hard for some obese people to lose weight; they are constantly fighting internal homeostatic mechanisms that work to maintain their fat cell's "normal" weight.

But now, researchers have discovered that although you do have a constant number of fat cells throughout life, they are not the same cells. About 10% of them die each year and are replaced by new ones.

No one knows for sure what determines how many fat cells each person has. But the findings open up interesting new avenues for weight control research. If we could determine what regulates the number of fat cells and then alter that regulation, or if we could slow the rate of fat cell division, we might have a new way to fight obesity.