T. Colin Campbell is a retired professor of nutritional biochemistry at Cornell University who started his career doing research on how to make animals grow faster. His goal was to promote better health by advocating the consumption of more meat, milk and eggs.

Then, while he was a young researcher working on a project to help stamp out malnutrition in the Philippines, he came to a turning point in his life's work. Now he's on a mission to share his compelling research on nutrition and diet with the world. He wrote a book called "The China Study," (BenBella Books, 2005) based on his years of research showing the connection between nutrition and heart disease, diabetes and cancer. The study was the culmination of a 20-year partnership among Cornell University, Oxford University and the Chinese Academy of Preventive Medicine.

In the book he concludes, "People who ate the most animal-based foods got the most chronic disease. Even relatively small intakes of animal-based food were associated with adverse effects. People who ate the most plant-based foods were the healthiest and tended to avoid chronic disease."

Here are Campbell's answers to our questions about his research:

Q. Could you tell us briefly about the genesis of The China Study?

A. In 1981, the Chinese government announced the results of a nationwide survey of cancer mortality for 2,400 counties, which showed that cancer was far more common in some areas than in others. Geographic localization was far more intense than in the U.S. because the vast majority of people in China resided in the same place all their lives and consumed locally produced food. Americans move around and consume food from places far and wide, making it virtually impossible to do such a study.

Also, dietary lifestyle characteristics of people in rural China were substantially different from people in Western societies. These conditions presented an unparalleled and unique opportunity to compare diet, lifestyle and disease mortality rates with Western societies. It also allowed us to compare our results with our extensive laboratory animal findings obtained during the previous 15 years. I especially wanted to record as many different kinds of diet and lifestyle factors as possible in order to get information on "big picture" questions that seemed to be so contentious in the scientific and public communities.

Q. You claim that your research showed that the protein casein, which makes up 87 percent of cow's milk protein, promoted all stages of the cancer process. Are you saying that animal protein promotes cancer?

A. In our animal studies, casein as an animal protein promotes cancer, in spades. Of all the research my laboratory did, this may be the most convincing. In fact, our findings, done in so many ways, show that casein is the most relevant chemical carcinogen ever discovered. I have published the results in the very best peer-reviewed scientific journals. These findings also are consistent with similar promoting effects of casein on the development of experimental atherogenesis (the lesion leading to heart disease) and rising blood cholesterol levels, among other toxic events.

Q. Are you suggesting that we all become vegetarians?

A. I have never suggested that we should all be vegetarians because about 90 percent of vegetarians are still consuming food (i.e., dairy, eggs) with nutrient compositions that actually account for the adverse health effects of animal-based foods. Although consuming foods that trend in the direction of better health, vegetarians do not do what they could do. This suggests that vegans should do better, but they, too, compromise their potential benefits because they consume food that is highly processed. My recommendation is to consume a whole-food, plant-based diet without supplementing with added fat, salt, sugar and processed foods.

Charles Stuart Platkin is a nutrition and public health advocate, founder of DietDetective.com, and host of the new WE tv series "I Want To Save Your Life."