Dr. T. Colin Campbell, the Jacob Gould Schurman professor emeritus of Nutritional Biochemistry at Cornell University, is the co-author of The China Study, author of Whole: Rethinking the Science of Nutrition and was featured in the film Forks Over Knives. In his 70-plus years, he has written more than 300 research papers on diet, nutrition and health based on laboratory research and large-scale human studies in China and the Philippines. He founded the nonprofit T. Colin Campbell Center for Nutrition Studies, in Ithaca, New York.

The terms “vegan diet” and “plant-based diet” are often used interchangeably, but is there a difference?
In past years, most people that chose a vegan diet did so for ideological reasons, without fully understanding the scientific basis for this choice. As a result, the average vegan diet is not very healthy, nutritionally speaking—it’s much too high in total fat (about 30 percent of total calories) and refined carbohydrates (sugar and flour), often in the form of processed foods.

What are the main ecological and environmental benefits of a plant-based diet?
Methane production by livestock is a major contributor to climate change, responsible for as much as 50 percent of current greenhouse gas production, according to some sources. Even the livestock interest group with the Food and Agriculture Organization of the United Nations has estimated for at least the past 10 years that this contribution, although cited lower at 14.5 to 18 percent, outranks even the transportation sector.

The significance relates to methane production, which has a far higher capacity on a molecular level to trap and hold heat energy in the atmosphere than carbon dioxide, although it has a shorter life. Its effect multiplies because a faster rise in temperature leads to permafrost melting and an additional release of methane. Other serious problems associated with livestock production include loss of topsoil, contamination of groundwater, depletion of deepwater aquifers and pollution of oceans and reefs. 

Are all animal proteins harmful to health, or is dairy particularly detrimental?
The casein effect of dairy products on cancer can be generalized to all animal proteins, based on comparing its adverse effects on serum cholesterol, development of cardiovascular disease, excessive cell replication and inflammation. Just as important, diets with more animal protein are prone to include less plant-based foods that provide many essential health benefits.

Is there any evidence indicating that a diet that includes 5 to 10 percent of high-quality animal protein is less healthy than a 100 percent vegan diet?
To my knowledge, absent published direct evidence, there is a strong commonsense impression that a 100 percent plant diet is better than anything less. This is probably best answered by evidence from population-based studies showing a linear association of disease occurring with increasing consumption of animal-based foods, with zero disease at zero consumption of animal products. However, it’s also true that individual susceptibilities vary considerably. 

My best estimate is that it’s easier and safer to consume no animal-based food because it better allows emergence of new taste perception.

What can healthy eaters do to spread awareness of the benefits of such a lifestyle? 
Opportunities abound, including organizing a local showing of the film PlantPure Nation and a PlantPure pod program. You might enroll in the online plant-based nutrition certificate program partnered by the T. Colin Campbell Center for Nutrition Studies and Cornell University’s online curriculum and/or enroll in the Global Roots Health Experience conference this April in the Dominican Republic.

T. Colin Campbell, Ph.D., will be a keynote speaker on the Holistic Holiday at Sea cruise, departing on its 13th Caribbean Voyage to Well-Being on Feb. 27, 2016. For more information, call 800-496-0989 or visit HolisticHolidayAtSea.com. See ad, page 79.