Transcript: Do Flexitarians Live Longer?
What accounts for the benefits of a Mediterranean-style diet? An anatomy of health effects was published and the single most important component was the high consumption of plant foods. In contrast, fish and seafood consumption, the only animal foods promoted in the Mediterranean diet, did not seem to help.
In fact, if you look at the four major dietary quality scoring systems, which have all been associated with extending lifespan and lowering heart disease and cancer mortality, they all share only four things in common: more fruit, more vegetables, more whole grains, and more nuts and beans. They are all built on a common core of a diet rich in plant foods, whereas opposite food patterns, rich in animal foods and poor in plant-based foods (in other words, the Western diet), are associated with higher risks. So we need to optimize the food environment to support whole grains, vegetables, fruit, and plant-based proteins.
That’s one of the things all the so-called Blue Zones have in common; the longest living populations not only have social support and engagement, and daily exercise, but nutritionally they all center their diets around plant foods, reserving meat mostly for special occasions. And the population with perhaps the highest life expectancy in the world doesn’t eat any meat at all–the California Adventist vegetarians.
So if the primary benefits of the Mediterranean diet are due to all the whole plant foods, what if you went back to the famous PREDIMED study and created a pro-vegetarian scoring system? We know vegetarians live longer, but because a pure vegetarian diet might not easily be embraced by many individuals, maybe it would be easier to swallow if we just tell people more plant-based foods, less animal-based foods. But would just moving along the spectrum towards more plants actually enable people to live longer? They thought of this food pattern as a “gentle approach” to vegetarianism, figuring that if it improved survival it would be an easily understandable message for health promotion: more plant foods, less animal foods.
So you get points for eating fruit, vegetables, nuts, grains, beans, olive oil, and potatoes, but get docked points for any animal fats, eggs, fish, dairy, or any type of meat or meat products. Of course that means you get a higher score the more potato chips and French fries you eat. That’s why I prefer the term "whole food plant-based" diet since it’s defined by what you eat, not by what you don’t eat. When I taught at Cornell, I had “vegan” students who apparently were trying to live off French fries and beer; vegan does not necessarily mean health-promoting. But did it work? Regardless of healthy vs. unhealthy, if you give points to people for any kind of plant food, processed or not, and detract points for any kind of animal product consumption, do people with higher scores live longer? Yes. The maximum pro-vegetarian score is 60, but even just scoring 40 or more was associated with a 40% drop in mortality. In fact, there were so few deaths in the highest category of adherence to the pro-vegetarian diet, they had to merge the two upper categories for their analysis. This is evidence that simple advice to increase the consumption of plant-derived foods with reductions in the consumption of foods from animal sources confers a survival advantage, a live-a-longer-life advantage.
This modest change is realistic, affordable, and achievable because a sizable proportion of their population was already eating that way. So one can get a significant survival benefit without a radical shift to the exclusive consumption of plant foods–a more gradual and gentle approach more easily translatable into public policy. For example, a 41% drop in mortality rates in the United States would mean saving the lives of hundreds of thousands of Americans every year.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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