Grains are inferior in nutrition compared to animal product... I have a little quote from around 12th century AD.

" The Chinese noted with surprise and disgust the ability of Mongol warriors to survive on little food and water for long periods of time. The entire army could camp out without a single puff of smoke, since they needed no fires to cook. Mongol warriors carried fermented and dried dairy products with them which needed no cooking. They also consumed raw meat.(Raw tartare).. Compared to Chinese 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 against Chinese men who lived on gruel made from various grains. The grain diet of these Chinese soldiers stunted their growth and bones, rotted their teeth and left them weak and prone to diseases and sickness. In contrast the Mongol warrior ate mostly protein and fat, thereby giving him strong teeth, bones and strong body. Unlike the Chinese Jurched soldiers who were dependent on heavy carbohydrate grain diet, the Mongols could easily go a day or two without food and still maintain their strength and have enough energy to keep going. "

There you go... If milk and dairy was good enough for ancient warriors to keep them traveling for thousands of miles on horseback in all weather conditions, then it's good enough for me.