I spent some time this afternoon reading a little bit of this book on google books. So far I'm intrigued. I don't think there is anything really new here, but confirmation of a lot of what has already been discussed on this forum. He does tie together a lot of strands that typically aren't done in the diet literature that is out there.
He talks a lot about the defense mechanisms of plants and how they use certain chemicals to protect themselves from predators. Stuff like phytic acid, tannic acid, cyanide, polyphenols, protease inhibitors, lectins, etc. These are how these plants have protected themselves from predators. Many animals that consume a single food source often have some special genetic adaptation that allows them to do this. In fact it appears that of all the mammals, humans seem to be the least adapted to foods on this planet! He makes a good point that just because a food is natural, doesn't mean it is safe to eat, or safe to eat over a lifetime (such as allergenic foods). He gives the example that it is perfectly natural to die of mushroom poisoning. The mushroom is just doing what it is designed to do and that is to protect itself and others of it's kind from being eaten.
He makes some interesting observations about the conditions that would lead to a certain natural selection in the human species as far as adaptations to food. He mentions here:
Now assume in our case that people in a downright barren Europe 10,000 years ago were forced to drink milk to survive the harsh winters after the hoofed mammals had been hunted down to near extinction by humans. Lactose intolerance, the hitherto normal condition for adult humans (and animals), would then be a serious threat to survival; i.e. the inability to thrive on milk would exert a strong negative selection pressure. Assuming also the presence of a large enough founder population, after a few hundred generations it is highly possible that most lactose intolerant families had been eliminated, which also seems to have been the case among Scandinavian people.
This is an interesting perspective in light of cosmic catastrophes. One can think of other scenarios too such as a world devastated by fire where all the large fruit and nut bearing trees along with animal habitats have mostly burned to the ground leaving mostly grasses as the first pioneer species to recover. These being the only stable food source for several hundred years, people would have be forced to adapt to eating grasses and grass seed. Over time this may selectively breed out human families in those areas that couldn't thrive on these foods.
The biggest portion of the book that I was able to read online was the section on the dietary causes of heart disease. He does debunk a lot of the assumptions made about the causes of heart disease (such as a high fat diet for instance). He seems to point to dairy products and particularly milk as being one of the main culprits in the modern plague of heart disease.
He also has an interesting section on smoking, although google books only let me read the tail end of it. Now I can't seem to access it. Although he doesn't outright say smoking is good, he does point out that it has no causal relationship to heart disease.
He spends a lot of time going over the flaws in the diet studies that are out there. He points out that a vegetarian diet is typically not the greatest and shows that the pro-veg research doesn't isolate for certain factors. He makes the claim the vegetarians are typically more health conscious and thus would tend to choose better quality foods that non-vegetarians anyways. So it might have less to do with the lack of meat, but with the better quality foods and more vegetables in the diet that makes the bulk of the difference in these studies that show vegetarianism as a health diet alternative.
He seems fairly focused on the evolutionary model of explaining human dietary needs. This isn't surprising, I guess. I don't think this totally explains why humans are so poorly adapted to the foods commonly found on this planet. I think a 4D factor could explain some of these things too and in some cases may provide a simpler explanation. Another factor too could be the notion that humans didn't all descend from the same evolutionary pathway. Some might have evolved on this planet with the foods found here, while others may have been "planted" here and left on their own to figure out how to survive with the foods available.