If you gain weight after fat transfer to your lips, will your lip increase in size as well?

This has definitely been seen in the face when people have gained significant amounts of weight after a fat transfer.  The fat will retain the properties from the location it was taken.  So if you notice weight gain mostly in your abdomen and use this fat for the transfer, it will increase in size when you gain weight, even though it is in a new location. However to see a visible increase in the fat you would have to gain a significant amount of weight

   Viable fat in the lips could grow in a similar manner to fat elsewhere in the body.Kenneth Hughes, MDLos Angeles, CA

When fat is transferred to another part of your
body, it can have the potential to grow if you gain weight. The amount
of fat transferred to lips is
generally small (1-2 mL for each lip). Another option for lip
augmentation is filler with hyaluronic acid. This lasts about 12
months, but would not
change with weight fluctuations. I would
recommend that you consult with a board certified plastic surgeon to see which
option is the best for you.