The American Society of Plastic Surgeons advises you to be at a stable weight before getting a tummy tuck.  A tummy tuck, or abdominoplasty, removes excess fat and loose skin and tightens stretched muscles to give the abdomen a flatter appearance, but the outcome can be greatly diminished if your weight fluctuates.  Tummy tucks are major surgery, typically performed under general anesthesia.  In the US, the cost ranges from $4000 to $15,000 depending upon where you live and the complexity of the operation.  It is usually considered to be a cosmetic procedure and so not covered by health insurance.