The fat cells are present in the body in 2 types of layers:subcutaneous fat layer,just beneath the skin and visceral fat,which is present in the fat layer covering the visceral organs.The number of fat cells stays constant in both lean and obese individuals only the size of size of the cell changes due to the increased capacity of the cell for the storage of fat.An average human body has about 40 billion fat cells which can be as high as 100 billion fat cells in an obese person. Remember that as your body breaks down fat, the number of fat cells remains the same; each fat cell just get shrinked.