In recent years there has been increasing interest in a whole food plant-based (WFPB) diet as a means of promoting health. “Plant-based” means no animal products, and “whole foods” means minimally processed plants, so that micro-nutrients aren’t lost, and salt, sugar, fat, and chemicals aren’t added. An approximate definition of the WFPB ideal would be “vegan minus junk food.”
The nutritional biochemist T. Colin Campbell, Ph.D., is perhaps the best-known WFPB advocate, especially through the movie Forks Over Knives and the book The China Study, though among the increasing numbers of WFPB advocates, Caldwell Esselstyn, M.D., and Dean Ornish, M.D., are particularly well-known for their work on preventing, slowing, and reversing the progression of heart disease.
(Full disclosure—I have been on a WFPB diet for three and a half years.)
How Not to Die by Michael Greger, M.D., co-written with Gene Stone and containing 123 pages of endnotes, is an important contribution to making the WFPB literature available to the general public. Part 1 of the book contains 15 chapters, each devoted to one of the 15 leading causes of death in the United States, and to the ways that a WFPB diet (and other lifestyle elements like exercise and not smoking) can reduce their impact. The titles of the chapters are “How Not to Die From…”
1. Heart Disease
2. Lung Disease
3. Brain Disease
4. Digestive Cancers
7. High blood Pressure
8. Liver Disease
9. Blood Cancers
10. Kidney Disease
11. Breast Cancer
13. Prostate Cancer
14. Parkinson’s Disease
15. Iatrogenic Causes
Part 2 of the book discusses “Dr. Greger’s Daily Dozen”—a recommendation for WFPB ingredients the author suggests for maximizing health. These are (preceded by the suggested number of daily servings of each):
- 3 Beans
- 1 Berries
- 3 Other Fruits
- 1 Cruciferous Vegetables
- 2 Greens
- 2 Other Vegetables
- 1 Flaxseeds
- 1 Nuts
- 1 Spices
- 3 Whole Grains
- 5 Beverages
- 1 Exercise
All WFPB advocates have a common message: avoid animal products and processed foods + eat a wide variety of minimally processed plant foods. However, each WFPB author has an outlook that is in some ways distinctive, and that contradicts minor recommendations of others. For example, Campbell suggests minimizing the intake of nuts, seeds, avocados, and olives because they are high-fat (and Esselstyn, with his focus on heart disease suggests avoiding them), while Greger recommends eating nuts (though just a handful a day) because of their high nutrient content. Similarly, Campbell doesn’t recommend plant juices and smoothies because they bypass the initiation of digestion with saliva in the mouth, while Greger advocates plant beverages because of all the nutrients they contain.
Greger’s distinctive contribution in How Not to Die is his disease-by-disease review of studies showing positive effects of specific plant foods for preventing or ameliorating each (and of animal foods for causing or exacerbating them). He also has a website, nutritionfacts.org, that includes many brief videos.
Since I am not a nutritionist, I do not know whether other studies exist with different results—though Greger’s inclusion of footnoted qualifying comments are a hopeful sign. Of course, as he recognizes, many of the cited studies are small-scale one-shot affairs, so the effects might wash out on replication. His argument is that, unlike the negative side effects associated with medications, the side-effects of, for example, eating your spinach are only positive—so why not include this or that plant food in your diet?
(I should mention in passing my skepticism about Chapter 12, "How Not to Die from Suicidal Depression." It is one thing to claim that exercise and foods have an effect on mood, and quite another, in the chapter title, to claim an effect on the rate of suicide. This criticism applies to the title of the book, and to the other chapters. I understand that a chapter title like “How to Reduce Your Odds of Getting Breast Cancer” is not as punchy as “How Not to Die from Breast Cancer.” But naive readers need to understand that the book is offering tips for good health, not guaranteed cures.)
Nutrition is incredibly complex, so even if the studies Greger cites of the effects of a given food on a particular disease are correct, there is no way of knowing whether the interaction with other foods and/or medications would increase, decrease, or leave the effects unchanged.
In an earlier Psychology Today post, I reviewed T. Colin Campbell’s book Whole: Rethinking the Science of Nutrition. Here is a quotation from that book that I used to make the point about nutritional complexity, and my comment on that passage:
“Calcium decreases iron bioavailability by as much as 400%, while carotenoids (like beta-carotene) increase iron absorption by as much as 300%. Theoretically, in comparing a high-calcium, low-carotenoid diet with a low-calcium, high-carotenoid diet, we might see an 800-1,200 percent difference in iron absorption ... for some nutrients, tissue concentrations varying by more than 10-20 percent can mean seriously bad news ... Nutrient pairs that were found to influence each other and in turn, to influence components of the immune system include vitamin E-selenium, vitamin E-vitamin C, vitamin E-vitamin A, and vitamin A-vitamin D. The mineral magnesium influences the effects of iron, manganese, vitamin E, potassium, calcium, phosphorus, and sodium, and through them the activities of hundreds of enzymes that process them; copper interacts with iron, zinc, molybdenum, and selenium to affect the immune system; dietary protein exerts different effects on zinc; and vitamin A and dietary fat affect each other’s ability to influence the development of experimentally created cancer ... the common belief that we can investigate the effects of a single nutrient or drug, unmindful of the potential modifications by other chemical factors is foolhardy. This evidence should also make us extremely hesitant to “mega-dose” on nutrients isolated from whole foods. Our bodies have evolved to eat whole foods, and can therefore deal with the combinations and interactions of nutrients contained in those foods. Give a body 10,000 mg of vitamin C, however, and all bets are off.” (Pp. 70-71.)
The take-away message from the nutrition-specific parts of [Whole: Rethinking the Science of Nutrition] is that nutrition is incredibly complex, with millions of working parts, interactions, and feedback loops, so that there is no known straightforward relationship between the amount of a given nutrient that your body takes in and either the amount it actually uses or its effect on a specific disease.
Of course, Campbell’s point was about specific nutrients, rather than a specific plant, like spinach, with all its biochemical complexity. Still the overall point about nutritional complexity makes me wonder whether Greger’s idea of using specific plants for specific illnesses—as opposed to a WFPB diet having positive health effects across a range of illnesses—may be oversold.
I am a psychologist, not a nutritionist, dietician, or physician, so in reading How Not to Die my health psychology interest is in how we can get people to increase their intake of plants. That is, which readers might be turned on by the book, and which might be turned off? I can see three kinds of readers who might gravitate to the book:
- For individuals who have, or who have a family history of, a particular disease, and who are asking themselves “Can I change my diet in a way that might help?” the book contains specific recommendations, and the endnotes offer places for readers to pursue their interests.
- For highly organized people who like to-do lists that they can check off, the book offers clear suggestions.
- For people on a WFPB diet who want a reference volume, How Not to Die is a useful resource.
On the other hand, for those who like simplicity, all that is needed for a WFPB diet is to eat a wide variety of minimally processed plant foods—as much as you want, whenever you want. There are lots of new vegetables, fruits, and grains to try that can be found in Asian, Latin American, African, and other food markets; and preparation instructions and recipes are readily available on the internet.
Check out my most recent book, The Myth of Race, which debunks common misconceptions, as well as my other books at Amazon.com. Visit my website at www.jeffersonfish.com.