Thank you for your picture. You should not gain weight to have a procedure. You should first have liposuction of your abdomen, hips and back. This amount of fat graft to your buttocks for shaping. If you are going for the "big booty" look you do not have any fat for that. After about 6 months then have a tummy tuck to contour your abdomen and further contour your waist which will further enhance your buttocks.