you`re born with the same amount of muscle and fat cells,they either shrink or expand but the numbers remain the same.
watch fucking Jeff trip me up on this. 
This used to be correct, but today you can actually voluntarily reduce the number of fat cells in your body. One way is by undergoing cryolipolysis (CoolSculping). This was first used in 2009. Another way is by undergoing liposuction. This has been available since 1975.
When fat cells are either removed or frozen to death, they do not regenerate. However, like you said, individual cells can still expand. So, it is possible to get fat with fewer fat cells if you overeat based on your metabolism. The number of muscle cells in our bodies is constant. At this time, there is no way to voluntarily reduce skeletal muscle cells them without cutting them out which no one in their right mind would do.
Based on my personal experience, cool sculping is an excellent way to sculpt your body by ridding it of unwanted fat cells, i.e. "Love handles." Not only is this noninvasive, which liposuction is, it accomplishes what was intended. No more love handles. Yahoo!