Is there a hormonal or physiological change after a tummy tuck or body lift that causes intense increased sexual desire?

This is an interesting question!  There is a relationship between sex steroid hormones and adipose tissue, but I don't know of any solid links between a change in libido and body contouring surgery.  I would suggest the effect was more due to your postoperative results.  Many people see an immediate physical and psychological benefit especially if a lot of skin was removed.  In either case, sounds like it worked out well.

It is not rare to have a patient describe these sexual symptoms after any form of a tummy tuck procedure. It is likely that the resultant and sometimes inadvertent pubic lift from the procedure changes the location/angle of the clitoris and makes it sensitive to pressure/stimulation.