The phrase “plant-based diet” is being tossed around a lot these days. The Skeptical Cardiologist never knows what people mean when they use it and so must assume that most of the world is also puzzled by this trendy term.
For some, a “plant-based diet” is what vegans eat. Veganism combines a diet free of animal products with a moral philosophy that rejects the “commodity status of animals.”
Vegans are the strictest of vegetarians, eschewing milk, fish, and eggs.
One plant-based diet advocate in the introduction to a special issue of the Journal of Geriatric Cardiology wrote that “a plant-based diet consists of all minimally processed fruits, vegetables, whole grains, legumes, nuts and seeds, herbs, and spices and excludes all animal products, including red meat, poultry, fish, eggs, and dairy products.”
You will notice that this cardiologist “excludes all animal products” and that the qualifying phrase “minimally processed” crept into the definition.
The so-called documentary “Forks Over Knives” brought the phrase “whole food, plant-based diet” to national prominence. The film focused on the diets espoused by Caldwell Esselstyn and T. Colin Campbell. Since its release in 2011, a whole industry based on the Forks Over Knives (FON) brand has been launched. FON uses the following definition:
“A whole-food, plant-based diet is centered on whole, unrefined, or minimally refined plants. It’s a diet based on fruits, vegetables, tubers, whole grains, and legumes; and it excludes or minimizes meat (including chicken and fish), dairy products, and eggs, as well as highly refined foods like bleached flour, refined sugar, and oil.” [emphasis added]
I’ve written detailed posts on the Esselstyn diet here and here. I think it is needlessly restrictive and not supported by scientific evidence. (Esselstyn’s website and book state unequivocally “you may not eat anything with a mother or a face” and “you cannot eat dairy products,” which differs from the FON definition.)
The key new terms to note in the FON approach are:
- Whole food, defined by the Oxford English Dictionary as “food that has been processed or refined as little as possible and is free from additives or other artificial substances.”
- Unrefined or minimally refined, with refined defined by that dictionary as “impurities or unwanted elements having been removed by processing.”
The FON definition for a plant-based diet then is similar to our first definition — minimally processed vegan — but allows (at least theoretically) minimal meat, dairy and eggs. The FON Esselstyn/Campbell diets choose to define vegetable oil, including olive oil, as highly-refined foods and do not allow any oils.
Diet Ranking Definition
U.S. News and World Report publishes an annual rating of diets based on the opinion of a panel of nationally-recognized experts in diet, nutrition, obesity, food psychology, diabetes and heart disease.
That publication defines a plant-based diet as “an approach that emphasizes minimally processed foods from plants, with modest amounts of fish, lean meat and low-fat dairy, and red meat only sparingly.”
This plant-based diet definition is radically different from the first two I described. Notice now that you can have “modest amounts” of meat and dairy, foods that are anathema to vegans. Also, note that “low-fat dairy” is being recommended, which involves processing and adulterating what are in my opinion healthy natural dairy fat foods, making it highly processed. Lean meat is preferred, and red meat avoided.
I was happy to see that, for the first time, the Mediterranean diet ranked as U.S. News’ best diet overall but shocked to find that the Mediterranean diet came out on top of the list of “Best Plant-Based Diets.”
The plant-based diet of vegans or of “Forks Over Knives” is drastically different from the Mediterranean diet.
For example, olive oil consumption is emphasized in the Mediterranean diet, whereas the Esselstyn diet featured in FON forbids any oil consumption.
The FON/Esselstyn diets are very low in any fats, typically <10%, whereas the Mediterranean diet is typically 30% to 35% fat.
Esselstyn really doesn’t want you to eat nuts and avocados, because he thinks the oil in them is bad for you. This is nuts! I’m handing out nuts to my patients just as they were given to the participants in the PREDIMED randomized trial showing the benefits of the Med diet.
The Ornish Diet
I have critiqued in detail Dean Ornish’s claims to have scientific proof that his diet/exercise/meditation program “reverses heart disease” here. The bottom line is that these claims are not supported, and that is why his program is not recommended by the American Heart Association or the U.S. Dietary Guidelines for Americans.
I was pleased to see that the Ornish diet has slipped from third to fourth place in the U.S. News and World Report overall best diet recommendations for 2020. However, the Ornish diet seems to have risen to #1 for “heart-healthy diets,” something I strongly disagree with.
The blurb associated with Ornish states it is “ranked highly for heart health again this year due to its holistic and evidence-based approach shown to help prevent and even reverse heart disease.”
It is not evidence-based, although it is holistic in the sense that a regular exercise plan and stress mediation is part of the program, something that should be part of any lifestyle approach to heart disease.
My Plant-Based Diet
Since the term “plant-based diet” apparently means whatever a writer would like it to mean, I have come up with my own definition.
With the Dr. P Plant-Based Diet©, your primary focus in meal planning is to make sure that you are regularly consuming a large and diverse amount of healthy foods that come from plants.
If you don’t make it your focus, it is too easy to succumb to all the cookies, donuts, pies, cakes, pretzels, chips, french fries, breakfast bars, and other calorie-dense but nutrient-light products that are cheap and readily available.
I, like the plant-based diet definers of yore, have taken the liberty of including many vague terms in my definition. Let me see if I can be more precise:
- Regularly: at least daily
- Large amount: three to four servings daily
- Healthy: a highly contentious term that, like “plant-based,” one can twist to mean whatever one likes
My take on “healthy” can be seen on this blog. I’m not a fan of plant-based margarines. Added sugar, whether from a plant or not, should be avoided, and the best way to avoid added sugar is to avoid ultra-processed foods.
Ultra-processed foods, by the NOVA definition are formulations of several ingredients which, besides salt, sugar, oils and fats, include food substances not used in culinary preparations, in particular, flavors, colors, sweeteners, emulsifiers and other additives used to imitate sensorial qualities of unprocessed or minimally processed foods and their culinary preparations or to disguise undesirable qualities of the final product.
Ultra-processed foods account for 58% of all calories in the U.S. diet and contribute nearly 90% of all added sugars.
I do like the food writer Michael Pollan’s simple rules to “Eat Food. Mostly Plants. Not Too Much.” and this New York Times piece summarizes much of what is in his short, funny, and helpful “Food Rules” book:
“[Y]ou’re much better off eating whole fresh foods than processed food products. That’s what I mean by the recommendation to eat “food.” Once, food was all you could eat, but today there are lots of other edible foodlike substances in the supermarket. These novel products of food science often come in packages festooned with health claims, which brings me to a related rule of thumb: if you’re concerned about your health, you should probably avoid food products that make health claims. Why? Because a health claim on a food product is a good indication that it’s not really food, and food is what you want to eat.”
On Dr. P’s Plant-Based Diet© you can add butter to your leeks and green onions. You can add eggs (with yolks!) to your sautéed onions, tomatoes, and peppers. And you can eat salads full of lots of cool different plants for lunch.
To answer my titular question: If you are using Dr. P’s definition of a plant-based diet, then you definitely should be on one.
Anthony C. Pearson, MD, is a noninvasive cardiologist and professor of medicine at St. Louis University School of Medicine. He blogs on nutrition, cardiac testing, quackery, and other things worthy of skepticism at The Skeptical Cardiologist, where a version of this post first appeared.
Last Updated December 11, 2020