For years massive research funds have been flowing into weight-loss or diet pills.
But recently scientists tried a different approach: the brain.
In mice scientists found a circuit that involved specifick neuron cells inside the brain. With the right chemical they could ' block' or 'unblock' the signal and essentially make the mice experience hunger or loose their apetite.
It needs to be determined if humans have a smilar circuit and if other forms of switches exist. Turn off pain, feeling or increasing certain sensations.
more reading can be done here:
A neural basis for melanocortin-4 receptor–regulated appetite (original article)