I was very curious exactly how the fat leaves our bodies. Today I did a little digging and this what happens to the FAT
Some of the fuel you use for maintaining normal body functions and for exercise comes from two ready sources: glucose and triglycerides. Both circulate in the blood, so they are easily available as fuel sources, even though they are in relatively short supply. More abundant supplies are found in the liver and stored fat cells.
If the demands of your activity are greater than what circulating fat and glucose can supply, your body will need to dip into the stored energy in the liver and fat cells. Hormones in the body activate an enzyme called lipase that tells the fat cells to release triglycerides. The triglycerides are broken down into glycerol and free fatty acids and enter the bloodstream. The liver recycles the glycerol, and the muscles use the free fatty acids for energy. When the free fatty acids are consumed by working muscles and other tissues, they are converted to heat, water, carbon dioxide and adenosine triphosphate, or ATP. Your body releases heat through your skin, water as you sweat and ; carbon dioxide as you breathe it converts the energy in the bonds of ATP into energy your body can use.
BOTTOM LINE: The fat leaves our bodies by SWEATING and BREATHING, both of which we have to workout to accomplish!