Something to consider:
http://en.wikipedia.org/wiki/AdipocyteEven after marked weight loss, the body never loses adipocytes. As a rule, to facilitate changes in weight, the adipocytes in the body merely gain or lose fat content. However, if the adipocytes in the body reach their maximum capacity of fat, they may replicate to allow additional fat storage.
Adult rats of various strains became obese when they were fed a highly palatable diet for several months. Analysis of their adipose tissue morphology revealed increases in both adipocyte size and number in most depots. Reintroduction of an ordinary chow diet[clarification needed] to such animals precipitated a period of weight loss during which only mean adipocyte size returned to normal. Adipocyte number remained at the elevated level achieved during the period of weight gain.[5]
In some reports and textbooks, the number of adipocytes can increase in childhood and adolescence, though the amount is usually constant in adults. Interestingly, individuals who become obese as adults, rather than as adolescents, have no more adipocytes than they had before.[6]
People who have been fat since childhood generally have an inflated number of fat cells. People who become fat as adults may have no more fat cells than their lean peers, but their fat cells are larger. In general, people with an excess of fat cells find it harder to lose weight and keep it off than the obese who simply have enlarged fat cells.[7]
According to research by Tchoukalova et al., 2010, body fat cells could have regional responses to the overfeeding that was studied in adult subjects. In the upper body, an increase of adipocyte size correlated with upper-body fat gain; however, the number of fat cells was not significantly changed. In contrast to the upper body fat cell response, the number of lower-body adipocytes did significantly increase during the course of experiment. Notably, there was no change in the size of the lower-body adipocytes.[8]
Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index without a significant increase in the overall number of adipocytes in adulthood.[6]
