I'm waiting for someone to invent the implantable chip that converts blood sugar into heat/light purely with the intention of wasting that energy.
Grab enough power to monitor blood sugar, to make sure you aren't putting someone into a coma, but otherwise just try to burn an extra few hundred calories a day.
You're thinking too fancy - with our technology today, we could install a bypass valve at the pyloric sphincter that just dumps chyme into a stoma appliance/bag.
That's interesting. Seems like a low tech solution would be to give blood every day. I wonder if somebody has already invented the blood donation diet.
Grab enough power to monitor blood sugar, to make sure you aren't putting someone into a coma, but otherwise just try to burn an extra few hundred calories a day.