Small weight fluctuations between 10-15 pounds will have no impact on the results, but excessive weight gain (over 20 pounds) will stretch the skin and the abdominal muscles. Fat cells are removed during a tummy tuck, so you may find that you are more likely to gain weight in other fat cells stored in your body – be it the back, butt, thighs, or lower abdomen. The skin and intestines can continue to store fat if you gain a large amount of weight, thus increasing the thickness of your tummy to give you a “flabby” look.