>I keep hearing this same thing: that we need to keep growing grains and
>feeding people mainly grains or there's going to be mass starvation.  I'd like
>to be able to refer to some research that's been done on the subject. Do you
>know of any such work, demonstrating at least in theory that as many people could be as well nourished
>on the same amount of land used for fruits, veggies and meat as for grains?

Unfortunately (!!!), when it comes to intensive agriculture, grain wins the quantity battle every time. I recently read a figure that absolutely astounded me (I don't have the source handy at the moment - I'll look it up tonight). It had to do with how many loaves of bread can be produced from a wheat farm, and how many people those loaves could feed over the course of a year. The number was astronomical, and it's the reason "not growing" wheat is subsidized. The resultant "food" is so plentiful - and so cheap - it becomes uneconomical for farmers to grow it if left to the market to decide price. (Apparently at one point in time in the U.S. there was such an overabundance of wheat there was no place left to store it).

That said, my preference (of course :) would be to replace some of those intentionally fallow wheat fields with fruits and veggies. Not to mention all of the hilly or mountainous potential grazing areas available worldwide. Will I get my wish? Probably not (at least during the rest of my lifetime).