Splitting of triglycerides produces free fatty acids and glycerol in adipose cells. Adipocytes lack the emzyme glycerokinase which is essential for synthesis of α-glycerol phosphate from glycerol. The glycerol released by lipolysis must be transported to the liver for further metabolism in generating glucose for cellular respiration.
http://www.medbio.info/horn/time%203-4/h...
A moderate increase in aerobic exercise activity combined with weight loss produces a change in the mitochondria already present in muscle tissures. The first change is an increase in the mitochondrial working surfaces so they each swell in size. This allows each mitochondria to do more work, produce more ATP for activity.
Once their full potential is reached and the level of exercise still is placing a demand, then there will be mitochondrial replication and growth in the skeletal muscle. Skeletal muscle mitochondria become very extensive and branch into spaces between the muscle fibers. They are shaped and positioned to support the increasing muscle function.
This is why there is a slight delay in observable changes in muscle tone from exercise stress. The first changes are inside the muscle cell's organelles then the muscle cells increase along with the number of mitochondria.
http://books.google.com/books?id=D89d38P...