A moment on the lips...a lifetime on the hips!

http://www.sciencenews.org/view/generic/id/31755/title/A_moment_on_the_lips

When you lose weight, you may think you're losing those fat cells, but you're not! Neuroscientist, Kirsty Spalding and her colleagues, of the Karolinsha Institute in Stockholm, Sweden, used an a technique Spalding originally developed to figure out whether neurons replicate, to attempt to answer the question of whether people gain and lose fat cells as their weight moves up or down the scale. Above-ground nuclear bomb tests, during the Cold War, caused levels of the radioactive isotope, C-14, to skyrocket. Since then the level of C-14 has slowly decreased. Humans take in this isotope by eating herbivores, which incorporates C-14 through photosynthesis. Ergo, the level of C-14 in human cells created in a given year reflect the level of the isotope in the atmosphere that year. Spalding and her team used C-14 to determine how often fat cells turn over. After trackin the "birth dates" of fat cells in adults, Spalding found tat adults loose about ten percent of fat cells each year, but all those cells are replaced. The researchers reported in Nature on August 4, that obese people have about twice the number of fat cells as normal-weight adults, and the cells are bigger. Spalding and her colleagues concluded adults maintain a fixed number of cells throughout life. As cells die, the same number is replenished, and when people gain weight they do not gain fat cells, rather the cells are packed with lipids and expand in size.
The director of the Center for Human Nutrition at Washington University School of Medicine in St. Louis, Samuel Klein, doesn't agree with Spalding in the fact that people don't make more fat cells as they gain weight, but he does agree that fat cells in obese people are larger than in lean people. Klein says, "If we never made more fat cells, they'd become huge in size, and that just doesn't happen." He states that there is a limit of how much lipid can fit in a fat cell, about 1.5 micrograms, and he believes some people gain much more weight than can be accounted for by the fat that can be stored. "Its fat cell size, not number, that causes metabolic problems," Klein says, because stuffed fat cells leak fatty acids or ive off hormones that trigger inflammation, or lead to high blood pressure, heart disease and diabetes. Small fat cells on the other hand, don't release those kinds of troublesome molecules.


I don't think I've ever really thought in depth about what's happening inside the body, while someone is gaining weight. I would have assumed that as you gained and lost weight, that you would gain and lose those fat cells, and it's interesting to me to read that that's not necissarily true. It's also interesting to read tw different opinions from two different researchers, it shows that there is still more researching to be done!