... there is a reason microwave ovens are designed to keep the microwaves from leaving the oven and why microwave-based weapons are being tested by the military.
George Foreman realized this as well, which is why he went the way of the Foreman Grill....
... but most electromagnic radiation, particularly something that was designed to deliver enough energy to cook things could be harmful at very close ranges (when it is radiating... I am not making any claims about the 'quality' or 'safety' of the food after it is cooked) ... particularly the eyes which have little natural blood flow to cool the area and are very susceptible to radiation (as you know, everyone wants to 'look into' the microwave to see their food cooking or popcorn popping). But the issue here is close range... electromagnetic energy density decreases rapidly with range from the source so lots of shielding is required to keep those eyes safe at close range (inches!)
Anyway, I think most military High-Power Microwave weapons development efforts are geared toward destroying electronics (not the same effect as heating human flesh) and the ones that are non-leathal or leathal to humans are either much higher in frequency (mm-wave, technically still microwaves, but not in the same class as far as frequency and how materials/flesh behaves when exposed) or much lower in frequency. (I think the lower frequency, non-lethal ideas and not designed to 'heat' you up but to resonate your body structures to make you sick).