This is what Mongol MREs looked like

It is believed that Napoleon who coined the phrase "An army marches on its stomach."

The adage was as true then as it was in ancient times, and for the Mongols who traveled thousands of miles to conquer and plunder, eating was a daunting task.

Because of their lineage as nomads and herders, the Mongols perfected how to travel light and still be able to fill their bellies. Sure they lived off their conquered lands, but between engagements they had their own version of berserker Rip-Its.

For Mongols on the move, the food they carried was usually dried. The hordes would carry dehydrated foods like dried meat, dried curd, and 10 pounds of milk dried down to a paste.

Take the dried milk for instance. To make it, the Mongols would evaporate the milk in the sun in which it turned into a chalk-like substance that made it easy to transport. Once mixed with water, the dried milk paste turned into a low-carb fatty and quite possibly the world's first protein shake that would suppress his appetite.

Another use of the milk was turning it into an alcoholic drink known as " kumiss" or "airagh." This was their preferred drink and was made from mare's milk. Rubruck mentions that the Mongols made kumiss by using "a great quantity of milk, which is as sweet as cow's as long as it is fresh, they pour it into a big skin or bottle, and they set to churning it with a stick prepared for that purpose, and which is as big as a man's head at its lower extremity and hollowed out; and when they have beaten it sharply it begins to boil up like new wine and to sour or ferment."

But when winter arrived, food became scarce for the horses, so they drank up all the milk themselves. With the lack of dairy, the Mongols sought other foods — ones that at time appeared stomach churning. The diet of a Mongol warrior involved just about everything that walked or crawled. According to Marco Polo:

They live off meat, milk and game and on Pharaoh's rats (marmots or jerboa), which are plentiful everywhere in the steppes. They have no objection to eating the flesh of horses and dogs and drinking mare's milk. In fact they eat flesh of any sort.

According to the 13th-century traveler Giovanni da Pian del Carpini:

They eat dogs, wolves, foxes and horses, and, when in difficulty, they eat human flesh. Thus, when they attacked a particular Chinese city, and their emperor himself conducted the siege, they found after they had besieged it a long while that the Tartars had used up all their supplies and did not have enough for all the men to eat, so they took one of every ten men to eat. They even eat the afterbirth which comes out of a mare with the foal. Furthermore, we saw them eat lice. They would say, 'Why should I not eat them when they eat my children and drink their blood?' We actually saw them eat mice.

If rations really got low, Marco Polo states that on "occasion they will sustain themselves on the blood of their horses, opening a vein and letting the blood jet into their mouths, drinking till they have had enough, and then staunching it." However, a Mongol warrior knew not to do this or to drink from the horse too long. Horse blood was the last resort.

Mongols lived on what we call today a paleo diet, but calling it "ketogenic" diet sounds more accurate, as it consists of high-fat, adequate-protein, and low-carbs. Such a diet based on protein leaves one full. Moreover, the Chinese who ruled the Jin Empire in northeastern China noted to their surprise that no puff of smoke came from the Mongol encampment and noticed that the warriors were able to survive off little food and water for long periods.

What the Chinese soon learned is that their soldiers could not go as long as the Mongols due to their dependence on carbs. Without a steady amount of carbs to stay energized, the Mongols could go for a few days before hunger set in since their bodies used the fats and proteins as energy. Overall, the Mongols were not fussy eaters as the accounts show.