If you use the scientific method, then you should be able to understand the anatomy and physiology of humans. Humans have taste receptors that receive sweet, salty, sour, bitter and savory (meat) tastes, therefore humans should eat foods with all of these flavors, not just the meat taste. The sweet taste receptors are not only located on the tongue but in other parts of the body so that the pancreas can properly produce insulin to uptake Sugar into the body. If you know anything about human physiology, then using the scientific method, it is very easy to deduce that humans are meant to eat sugars and carbohydrates (we can debate the amount of these higher or lower, but not that humans need them). Purely carnivorous animals such as lions do not have sweet taste receptors and therefore should not eat sugars and carbohydrates. Humans are not carnivorous animals like lions, we have sweet taste receptors and are meant to eat foods containing sugars (although not the types and the amounts in the diets most people eat).