Cell turnover Of Adipocyte

After marked weight loss the number of fat cells does not decrease (the cells contain less fat). Fat cells swell or shrink but remain constant in number. However, the number of fat cells may increase once existing fat cells are sufficiently full.

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 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.

However, in some reports and textbooks, the number of fat cell (adipocytes) increased in childhood and adolescence. The total number is constant in both obese and lean adult. Individuals who become obese as adults have no more fat cell than they had before.

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.[6]

According to a research by Tchoukalova et al., 2010, it has been reported that the body fat cells could have regional responses to the overfeeding studied in adult subjects. In upper body, an increasing of the adipocyte size was correlated with upper-body fat gain; however, the total fat cells were not significantly changed. In contrast to the upper body fat cell responses, a number of lower-body adipocytes were significantly increased during the course of experiment but there was no change in the cell size.

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.