Maybe you could elaborate on this third option you allude to.
Destabilize Mugabe (Britain would be glad to help) and install a provisional emergency government until the food crisis is past.
Set up food distribution points in areas friendly to the west. Staff with UN troops (they need something to do anyway).
Not EVERY country in Africa is as bad as Zimbabwe. Help those that are pro-West.
Air drops of food in areas where there is little infrasctructure could be effective if accompanied with propaganda, as in Afghanistan.
BUY mineral resources with food, making sure that monitors see that the thugs don't get control of it.
That's just what I can think of, not knowing that much about the resources available. I am certain that the administration is better at this than I am.
The "let them all starve" folks would hand a propaganda victory to those who want to control the Third World. This would be a disaster.