If we did that it wouldn't be feasible to have people kill themselves by starvation after the hero leaves service. I am strongly opposed to this idea.
The problem with a food bonus is it overpowers races with a food unit cost.
I thought the goal of your hero was to make farms nearly as valuable for investing. I now see that I was mistaken, and I must redo the bonus so it meets your 'evil' criteria (but without being overpowered).
Acerac: "-66.6% food consumption"
This nerfs the investment portion, but it retains the "Kill the player when I leave service" feature.
edit: Hmm, this suggestion was only partly evil. I need to make it full evil
Acerac: "-100% food consumption"