Photo by Sonny Mauricio on Unsplash

Last month, I urged readers to avoid eating beef because of how much land is required to produce it. I also noted the substantial emissions of methane (a potent greenhouse gas) that come from cows. But there is a much more personal reason to refrain from eating beef: it’s bad for your health. 

People eat beef for various reasons, the most common of which is its high protein content. Some people are convinced that a diet of animal protein (beef, dairy, lamb, chicken, or fish) is essential to getting an adequate supply of protein in their diet. 

In the classic book Diet for a Small Planet, Frances Moore Lappé argues that beans and rice contain complementary amino acids that provide the complete protein our bodies need. Animal protein is not essential for healthy bodies.

So, what difference does it make whether people get their complete protein from eating animals versus plants? 

In the early 1970s, Zhou Enlai, the Premier of China, was dying of cancer. Since cancer was poorly understood, he commissioned a nationwide survey of the death rates from four dozen types of cancer. Ninety-six percent of residents (880 million people) were surveyed. The study revealed a 100-fold range of cancer rates in the 2,400 counties in China. 

By that time, research had already concluded that genetics can only explain 2–3% of cancer. So, what was driving the inter-county variability? Was it pollution or diet? 

In the early 1980s, U.S. health researcher Colin Campbell and Chinese health researcher Junshi Chen formed a team to sift through Zhou Enlai’s vast health dataset. The lessons from that study are summarized in The China Study, written by Colin Campbell and his son.

The book's conclusions are profound: 

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.

Which diseases did they study? Citing studies from many countries, the Campbells found the impacts of an animal-based diet on coronary heart disease; colon, breast, and prostate cancers; type II diabetes; hypertension/high blood pressure; and obesity. They also cited increased risk of multiple sclerosis and type I diabetes for diets high in cow’s milk.

For many maladies, the amount of animal protein was not the only driver for disease. Sugar also affected diabetes and obesity, and for colon cancer, the amount of fiber (which comes from whole plants) seemed to be the primary mitigating influencer.

The authors also found significant differences between countries in which people die of diseases of affluence (where nutritional needs are exceeded) and countries where people die of diseases of poverty (where nutritional needs are not met and sanitation is poor). In the former, they found that most people die of various cancers, diabetes, and coronary heart disease. In the latter, most deaths are from pneumonia, tuberculosis, parasites, rheumatic heart disease, and malnutrition. 

A diet of primarily whole plant foods — such as fruits, vegetables, and whole grains — yielded a far lower incidence of heart disease, cancer, diabetes types I and II, and obesity as compared to a diet high in animal protein.

Not surprisingly, The China Study has been criticized. Denise Minger found low correlations between animal protein and many of the diseases identified by the Campbells. However, a rebuttal by the Campbells criticized Minger for relying on simple correlations that neglected the confounding influence of other variables that might drive relationships. The Campbells thought that Minger’s criticism didn’t consider the underlying mechanisms involved in these relationships.

Dave Asprey also argued with the Campbells’ findings, noting that in the 1970s, when China's data was collected, animal protein in China was often contaminated by a lack of refrigeration, mold, and high-temperature cooking. But Asprey failed to note that the Campbells’ book examines diet and health in multiple countries, many of which have refrigeration and use safer cooking methods. If meat contamination is a key driver of cancer, then why are the rates of cancer so much higher in the U.S, where rates of contamination are far lower?

Many of the conclusions of The China Study have been confirmed more recently. A vegan diet of whole plant food (fruits, vegetables, whole grains, legumes, nuts, and seeds) protects humans from coronary heart disease, colon cancer, obesity, type II diabetes, and hypertension/high blood pressure. The emphasis is on whole foods, as refined and processed carbohydrates lack the fiber and nutrients that come with whole plant foods.

So, for the sake of your health as well as the health of the Earth, you should avoid all meats, dairy, and eggs, and instead eat whole plant food. 

What does a healthy and delicious plant-based diet look like? Jenni Heerink answers that question and offers recipes in her Plant Strong Tri-Cities article being posted later this month.

Climate scientist Steve Ghan leads the Tri-Cities Chapter of Citizens Climate Lobby.

Editor’s note: Check out Greg Martin’s excellent article about plant-based diets: