The idea behind a tummy tuck or abdominoplasty is to contour the abdominal area, create a flat abdomen, make the waistline more defined, and remove excess skin and stretch marks. Most of the time, there is also some unwanted excess fat. Liposuction at the time of an abdominoplasty will improve the results by creating a better contour in the sides (flanks) and waistline. I include liposuction in every abdominoplasty without an additional charge. I believe that the optimal result cannot be achieved without it. Of course, there are always a few exceptions. See a board certified plastic surgeon to obtain the best possible recommendations.
Web reference: http://www.elpasoplasticsurgery.com/pages/dr-agullo