Here goes:
USA, England and Russia conducts a big military excersice. One night during the excersice a soldier from each nation gets lost, and the 3 of them meets up around a campfire. As they're eating they start talking about how they're treated in their respective armies. "In the Russian army we get 600 calories a day" says the Russian. "Well, that's nothing. In the British army we get 800 a day". "That's very nice, but in the US army we get 1000 calories a day" says the American. The Russian soldier is getting pretty annoyed by now, and says "That's Impossible! No man can eat that much cabbage!".