ignirtoq

Quantum field theory conserves mass-energy, so the new mass is coming from the energy in the Higgs field itself. It settles to a lower energy state and basically transfers that energy as mass to all of the particles that couple with it. Since it’s mass-energy and not just mass that generates gravitational distortions, the large-scale gravitational evolution of the universe probably won’t change, as this just moves things around a bit. It’s not creating energy out of nothing.

If the pig option included immune suppression drugs for the rest of your life, or for like 10 years until it wore out and you had to have another major surgery to replace it, mechanical valve plus blood thinners and a yearly blood draw sounds like the much better deal. I know blood thinners come with their own long term effects, but nothing compared to immune suppression.