Interesting...

[Rough Raiders]

"At your present rate, you will run out of Food in 787 Turns, so you should not build more than 68,444 Structures."

I got that today when I went to construct... Odd is it not?

[Ruddertail]

I had in once that I shouldn't build more than 250k + structures... I had about 30k land. :P

It happens whenever you're loosing food, though I haven't a clue why, it used to be only when you were actually critically low on food...