The most common, predictable, and trusted way to perform body contouring is with liposuction.  There are several variations of liposuction that include SAFELipo, SmartLipo, Vaser, and Power Assisted Liposuction (PAL).  The bottom line with liposuction is that is permanently removes excess fat cells during an outpatient surgical procedure. The results are immediate, durable, and predictable.
Note that liposuction or non-invasive fat reduction cannot address excess skin, only fat. If you have sagging skin, especially after pregnancy or weight loss, tummy tuck surgery (also known as abdominoplasty) is the only way to tighten stretched muscles and remove excess skin to restore a firm, smooth abdomen.