Re:Let's look at the look at Atkins (Score 1)

You're only half right, I'm afraid. Your credentials really only apply to dog nutrition, not human nutrition.

Dog and human diets are very different. Dogs are carnivores, while humans are (evolutionary) herbivores. Dogs have strong pointed jaws, with many sharp teeth for biting through flesh. Humans have jaws flush with the face, making it difficult to bite flesh. We have molar teeth and side-to-side jaw movement, designed for grinding tough vegetables and fruits. Our so-called "canine" teeth and other sharp frontal teeth have nothing to do with consuming meat and everything to do with devouring tough-skinned fruits and vegetables. (Think about biting through an apple with just back teeth.) Humans also produce ptyalin in the saliva for predigestion of fruits and veggies, which dogs and other carnivores do not.

Dogs have extremely short carnivore digestive tracts. (Meat must be digested before decomposition sets in too much, as some of the byproducts of decomposition are toxic.) This is one reason dogs do less well on low-meat diets. Shorter length affords less time to absorb nutrients from plant-based foods. In contrast, humans have a very long digestive tract, associated with herbivores, about 12 times the length of our entire body. For comparison, consider the diets of primates, our nearest evolutionary ancestors. Their digestive system very closely resembles ours, and their diet consists of lots and lots of fruit.

Which is not to say that there isn't some overlap. Dogs will consume vegetables occasionally. In the wild, dogs would get their minimal plant requirements from eating the digestive tracts of their prey. Also, dogs have been bred to be highly obedient, giving humans great leeway in controlling their diets, which is the only reason it's even possible to feed a dog a high-carb diet. (Try that with a cat, and see how far you get!) And while humans are, evolutionarily-speaking, primarily herbivores, it is quite likely that meat was a supplement to their diet (but only a supplement, and not the main course). I know many primates will occasionally use sticks to eat ants from an anthill. They probably consume small amounts of meat in other ways, too. This may technically classify them as omnivores, but saying so downplays the fact that over 95% of their diet is plant-based, and should be for us too, evolutionarily-speaking.