Long before KFC arrived in Mongolia:

As they moved, they milked the animals, slaughtered them for food, and fed themselves from hunting and looting. Marco Polo alleged that the Mongol warriors could travel ten days without stopping to make a fire or heat food, that they drank horses’ blood, and that each man carried with him ten pounds of dried milk paste, putting one pound of it in a leather flask of water each day to make his meal. The warrior carried strips of dried meat and dried curd with him that he could chew while riding; and when he had fresh meat, but no time to cook it, he put the raw flesh under his saddle so it would soon be softened and edible.

The Chinese noted with surprise and disgust the ability of the Mongol warriors to survive on little food and water for long periods; according to one, the entire army could camp without a single puff of smoke since they needed no fires to cook. Compared to the Jurched soldiers, the Mongols were much healthier and stronger. The Mongols consumed a steady diet of meat, milk, yogurt, and other dairy products, and they fought men who lived on gruel made from various grains. The grain diet of the peasant warriors stunted their bones, rotted their teeth, and left them weak and prone to disease. In contrast, the poorest Mongol soldier ate mostly protein, thereby giving him strong teeth and bones. Unlike the Jurched soldiers, who were dependent on a heavy carbohydrate diet, the Mongols could more easily go a day or two without food.

[from Jack Weatherford's Genghis Khan and the Making of the Modern World]