The process is as simple as it is terrifying: First, doctors clamp your head in a vice, then they drill some holes in your skull, and then they gently place some electrodes into that sweet spot of your brain that regulates metabolism. And how do they know they're hitting the right place? The target is conveniently situated next to your body's internal thermostat, so they know they've got it when you tell them that you're starting to feel really warm. Oh, did we mention you're awake during all of this?
Bashir, Sherwood, via ABC
"While you're in there, can you erase the time I caught my grandparents having a nooner?"
After these little cattle prods are firmly embedded in your gray matter, you spend a week in a special metabolic chamber while doctors fiddle around with the system, stimulating your metabolism by tweaking your brain's settings like it's a video game. The end result is that you feel satisfied after eating much less than you ordinarily would, because your brain is now a rat in a Skinner box that gets zapped when it gets too greedy.
Three human subjects have already undergone this procedure, and all have lost a considerable amount of weight. More experimentation is required to determine how much of the effect is attributable to the electrode stimulation and how much is due to the robots hollowing out your body and replacing your organs with carbon fiber.