Check out this November 2019 issue of Nature (there’s also a great piece on encouraging inquiry from students). An inhibition to (or absence of) something called PGRMC2 degrades the capacity to burn fat. Metabolism unwinds. Body temperature drops. Cells are inhibited at the mitochondrial level. That said, take note that the implications were only obvious as mice were overfed. The researchers reversed the condition with merely applying an PGRMC2 activator for already obese-diabetic mice.
Perhaps more interesting is that prior papers explored how exercise affects this very process (https://onlinelibrary.wiley.com/doi/full/10.1038/oby.2006.147). Therefore, although many readers may take this as yet another confirmation of the genetic expression excuse making, the reality is that tempering food intake and adding exercise is a form of genetic expression engineering.