However, I found the science on low-fat, "plant-based" (i.e., very low animal product) diets for the prevention and treatment of heart disease and other diseases very compelling. Some of the longest-lived societies in the world, the famous Blue Zones, eat high-carb, plant-based diets. However, I think it's too early to declare that animal foods and naturally occurring fats are necessarily bad for human health under all circumstances. It's likely that the astonishing improvements caused by the adoption of plant-based lifestyle programs are due to an interaction of many factors, possibly including restriction of animal foods, increased consumption of vegetables, better overall diet quality, reduction in processed foods and food additives, increased exercise, stress reduction, and improved interpersonal relationships. It's unclear which combinations of factors are responsible for which health effects, but it is clear that Dr. Ornish and Dr. Esselstyn are onto something important.
I was surprised by Dean Ornish's statement that "diet is the least interesting part of [my lifestyle plan]." He talked about the importance of interpersonal relationships and stress reduction on telomere length, a measure of aging. Dr. Ornish was very open about his depression and he addressed the importance of maintaining good mental as well as physical health. This is a part of our health that is often neglected, so I was grateful to Dr. Ornish for bringing it up. I was also intrigued by Dr. Ornish's concept of the spectrum of healthfulness. His diet is often characterized as extreme and difficult to stick to, but Dr. Ornish himself emphasized that diet and lifestyle are not black and white, that there is a spectrum of healthy choices.
Dr. Esselstyn's presentation was more focused on concrete health improvements, especially the mechanics of the cardiac health benefits of the lifestyle he and Dr. Ornish recommend. This lifestyle rapidly reverses atherosclerosis, and seems to have a role in preventing and treating certain cancers. Among the topics Dr. Esselstyn discussed were the role of polyphenols (naturally occurring plant antioxidants) in the prevention and reversal of heart disease. Dr. Esselstyn considers green leafy vegetables to be the best source of polyphenols, and recommends eating them five times a day. (No, that is not a typo.) Dietary polyphenols and exercise increase the levels of nitric oxide, a powerful vasodilator and anti-plaque agent. He also spoke on the unpleasant side effect on statins, and the need to rely on lifestyle therapies instead. Good lifestyles improve the function of endothelial membranes and prevent plaque accumulation.
I should disclose that I have a bias against Dr. Colin Campbell for having possibly misrepresented data on the landmark China study and his famous research on casein and aflatoxin (see here and here). That said, the China study is only observational and doesn't prove anything one way or the other. It's quite possible that the effects on mortality rates shown with animal product consumption are in fact due to socioeconomic status. This is a quite concerning cofounder in observational studies examining the role of saturated fat and animal protein in disease, since the people who eat the most meat in most societies are also the wealthiest.
Unfortunately, Dr. Campbell's presentation was mainly devoted to his hypothesis that animal protein and fat cause heart disease, cancer, and other ailments. He seemed to cite mostly the studies I mentioned above, which have been debunked, and observational studies, which are potentially ridden with cofounders that he did not discuss in his presentation. Nor did he mention the evidence that methionine-glycine balance were actually responsible for many of the benefits of low-protein diets. Given Dr. Campbell's very much evident anti-processed-food stance, it seems likely that many of the health improvements experienced on his diet are due to reduced consumption of processed foods.
I was disappointed by Brenda Davis' presentation, in which she discussed the "compelling nutritional advantages" of plant-based diets, because I felt that some of the things she said were misleading. In particular, she discussed the fact that a recent large meta-analysis originally found that saturated fat was harmful. After it was re-analyzed and in the new analysis saturated fat was not found to be harmful, and it was accepted for publication by a journal that had previously rejected it. Ms. Davis seemed to imply that the study's original conclusion was accurate, without mentioning the likelihood that it had been published because the methodology was improved. She also spoke about the dangers of EFA (essential fatty acid) deficiency, despite the fact that EFA deficiency is notoriously difficult to induce and was first discovered in people receiving total parenteral nutrition (intravenously delivered formula). The need for EFAs is very low in humans and EFA deficiency does not occur in people eating normal, whole food diets.
It's easy for many people in the ancestral health movement to deny, ridicule, or ignore plant-based doctors and the health benefits of their lifestyles, and perhaps vice versa. There are nutritional challenges associated with the complete elimination of animal products, and nutritional challenges associated with high-animal diets, but I don't think that at this point we can conclude that either of them is inherently unhealthy under all circumstances. If I have learned anything in the several months I have spent studying nutrition, it is of the imprudence of making grand pronouncements without sufficient evidence and consideration. Too often, nutrition is based on fervently professed, almost religious beliefs like "carbs cause diabetes," "fat causes heart disease," or even "a balanced diet must include low-fat dairy and whole grains." Nutrition should not be a religion and it's not about sound bytes. A healthful lifestyle should be based around scientific studies and genuine knowledge. Anyone who is interested in advancing science, searching for the truth, and exposing the hidden costs of our food system is my friend and my ally.
Raj Patel presented on a very different aspect of health and food. His presentation focused on the social justice issues surrounding access to healthy food and the environmental and human costs of cheap food. The poorest people in our society simply do not have the monetary resources to buy healthful food, while the best quality, most sustainable food is a resource accessible only to the wealthy. This has renewed my determination to buy more food at the local farmer's market, where I know that the soil, workers, and animals were treated well. Patel spoke about the changes in Cuban agriculture caused by the blockade, which reduced access to imported food and fertilizers. Instead of starving, the Cubans converted their monocultures into local, organic farms, and dramatically raised yields. These polycultures are also more resilient to climate change and adverse weather events. His presentation confirmed my ideas of sustainability and informed my future posts on the subject.