Campbell joined
MIT as a research associate, then worked for 10 years in the
Virginia Tech Department of Biochemistry and Nutrition, before returning to Cornell in 1975 to join its Division of Nutritional Sciences. He has worked as a senior science adviser to the
American Institute for Cancer Research, He is known in particular for research, derived in part from the China study, that appears to link the consumption of animal protein with the development of cancer and heart disease. Specifically, preliminary results from a large study involving 6,500 people in China showed a reduced risk of cancer, heart disease, diabetes, osteoporosis, and other illnesses among those who followed a plant-based diet. Campbell and his colleagues demonstrated that rats on a diet with 5%
casein (a milk protein) developed 75% fewer precancerous lesions in response to a carcinogen compared to those on a diet with 20% casein. He also said that "we could turn on or turn off cancer growth" by increasing or decreasing casein intake. Campbell's book,
The China Study, was influential in persuading President
Bill Clinton to adopt a vegan diet to lose weight and improve his heart disease. Campbell has followed a "99% vegan" diet since around 1990. He does not identify himself as a
vegetarian or
vegan, and uses the term "plant-based" instead because he said, "I didn't do this research to prove that vegetarianism or veganism are good ideas. I wanted the argument to rest on science, not ideology". He told the
New York Times: "The idea is that we should be consuming whole foods. We should not be relying on the idea that genes are determinants of our health. We should not be relying on the idea that nutrient supplementation is the way to get nutrition, because it's not. I'm talking about whole, plant-based foods". In 2013, Campbell debated Dr. Eric Westman — co-author of "The New Atkins for a New You", a physician, and an assistant professor at
Duke University who supports the
Atkins diet. Campbell cited a 2004 study funded by the
Atkins Diet company, which found that people on the Atkins diet not only suffered from constipation but also experienced higher rates of bad breath, headaches, muscle cramps, and diarrhea. He has been a member since 1978 of several
United States National Academy of Sciences expert panels on food safety, and holds an honorary professorship at the Chinese Academy of Preventive Medicine. Campbell is also on the advisory board of
Naked Food magazine. == Related media ==