Mention of the china study drives me batty now. I did read the book and I did go vegan. Out of curiosity, I decided to read the criticisms of the book (I didn't before because I thought it was clearly evident that animal protein makes cancer grow). Well! There are many criticisms of his theory. The most pertinent one to me was of the rat study.

In the book, he says that two groups of rats were given alfatoxin (an extremely potent carcinogen) and then fed a 5 percent casein/20 percent casein diet. Casein is a protein found in milk, and has been linked to cancer before. He goes on to say that after a year, lo and behold, the rats fed 5 percent animal protein did not have liver cancer and the rats fed 20 percent animal protein did have liver cancer. Wow! Casein, an animal protein, makes cancer grow, right? And no casein makes it not grow, right?

Not quite. What he doesn't mention in the book, is that all of the rats fed 5 percent casein succumbed to alfatoxin poisoning and all died, whereas the 20 percent casein rats stayed alive, but developed cancer. So basically the first group died before they could develop cancer.

This rat study was repeated later, but instead with a 20 percent casein diet versus 20 percent vegetable protein diet. Casein rats developed cancer, but the vegetable protein rats did not! This is really great. Just eat vegetable protein and no cancer for you! The problem with this is that the vegetable protein (incomplete protein) was missing lysine, an essential amino acid (which means that it is something your body needs but can't make on its own; you have to get it from what you eat), and when they added that, both the 20 percent casein rats and the 20 percent veggie protein plus lysine (now a complete protein too) rats developed liver cancer.

I'm no scientist, but it doesn't take one to hypothesize that maybe cancer does not need animal protein to grow, but just a complete protein (a protein that contains all essential amino acids). Casein is a complete protein, by the way.

So that was just the tip of the iceberg. Also, there was plenty of valid criticism of the way he portrayed the actual china study numbers. (Wheat actually has the highest correlation of death, heart attack and cancer, I believe) But you should read that for yourself. Look up China Study debunked.

I only made this comment to let others know who read the book that the 5 percent casein rat group died before the study was over, and to express my outrage that he did not mention that in the book. It definitely does not sound good to say, "well, the meat eating rats got cancer but these *dead* protein deprived rats over here didn't. Meat causes cancer."

Don't take it from me. Look it up yourself and read the mountain of text that is the critique of the china study and decide for yourself. For what it's worth, I also recommend reading the book "Wheat Belly" and reading the critique of that.

I think it's worth noting that no human society has ever developed a vegan diet -- basically, one avoiding all types of animal protein, like the article mentioned. There are species of mammals, including some primates, that eat an exclusively vegetarian diet. Chimpanzees, our closest living relatives, are *not* among them. (Chimpanzees usually eat plants, but when the opportunity presents itself, they will hunt and eat monkeys. They have also been observed engaging in cannibalism.)

That's not to say that a vegan diet can't be a healthy diet or that it might not be beneficial in some cases, only that it is not how humans evolved or what we are designed for. (Many aspects of modern life, like surviving long past the reproductive years, are not "natural," but I will take them thanks.)

Every person will need to decide for him- or herself what the healthiest diet is, whether that's a vegan diet, a vegetarian diet that includes eggs and some dairy, etc. Certainly, pretty much all Americans would benefit from eating more plants and *fewer* animal products.