The Inflammatory Diet
Why no, in fact you should not avoid certain foods to reduce your body's inflammation.
by Brian Dunning
March 13, 2018
Wellness, contend many promoters of healthy living, can most easily be achieved by avoiding the foods that cause inflammation; inflammation being the root cause of so many modern diseases. It's a mantra that's repeated virtually every time you hear a Hollywood celebrity preach about their diet, and every time you pick up a bestselling book in the Health & Wellness section. Cut out the foods that cause inflammation and add more foods that reduce inflammation, and instantly you'll be in charge of your own health. Those modern diseases, so symptomatic of our Western culture, the advocates claim, will simply fail to take a foothold in your inflammation-proof body. Today we're going to unpack this dietary belief and see if there really is such a thing as a food that can either trigger or reduce inflammation, and see if reducing it is even something you should try and do in the first place.
Here are a few specific claims harvested from the top results in a Google search for inflammation and diet:
- From mindbodygreen.com: A fiber-rich diet helps reduce inflammation by supplying naturally occurring anti-inflammatory phytonutrients found in fruits, vegetables, and other whole foods.
- From WebMD: An anti-inflammatory diet is widely regarded as healthy, so even if it doesn't help with your condition, it can help lower your chances of having other problems.
- From DrWeil.com: Along with influencing inflammation, this natural anti-inflammatory diet will provide steady energy and ample vitamins, minerals, essential fatty acids, dietary fiber, and protective phytonutrients.
- From EatThisNotThat: The typical American diet... is full of inflammation-inducing foods: fried foods, refined flours and sugars, hormone- and antibiotic-laden animal products, synthetic sweeteners, and artificial food additives.
- And just to show how prevalent these beliefs are, we even find it on Harvard Women's Health Watch: One of the most powerful tools to combat inflammation comes not from the pharmacy, but from the grocery store.
While sorting and collating and arranging all the research for this episode, I decided the best way to present it is in reverse. The basic claim we're evaluating is that you should eat a diet that reduces inflammation and thus reduce disease, and it turns out that every link in that chain is fatally oversimplified to the point that by the time we get to the end of the chain there is nothing left. So rather than funneling down to the conclusion, I'm going to start with the conclusion and then explain what's wrong with each of the assumptions supporting the claim. And that conclusion is — drum roll please — No. There is no sound science at all behind the idea that disease is caused by inflammation, or that inflammation is generally a thing to be avoided, that inflammation is even well-enough defined in this context, or that certain foods cause it and certain foods reduce it. When you hear a Hollywood celebrity or diet guru say that you should eat in such a way to reduce your body's inflammation, they are wrong. There is no reason to do such a thing, and there is not even such a thing to try and do. It's just another magically easy solution to a complicated problem. It sounds sciencey and magically easy solutions sell themselves, so it becomes wildly popular among the general public.
So let's start with the basics: What exactly is inflammation? Well the part that everyone knows is that it involves redness and swelling. It happens when your body is healing an injury or fighting infection. The capillaries dilate, allowing more blood to flow through, and also stretching open their pores, allowing white blood cells to escape the capillaries and inundate the damaged area. The chemical signal that triggers it is carried by inflammasomes which reside throughout the body and are one important component of your immune system. Thus, inflammation is your body's natural, healthy immune response to some problem that needs to be responded to. In general, inflammation is there for a good reason, and you don't want to interfere with it.
Inflammation can also be chronic, and this is where the alternative health advocates usually say intervention with diet is targeted. Chronic inflammation, however, is not just existent in the body with no cause. Rather, it's associated with a chronic illness or other condition. Type II diabetes and Alzheimer's disease are two examples where the relationship between inflammation and disease is a bit more complicated. In both cases, the attendant inflammation — in the brain in Alzheimer's, and in the pancreas in diabetes — may actually make the disease worse. However this is not to say that the inflammation is the cause of the disease; indeed, evidence indicates that the disease is the cause of the inflammation.
While some inflammation is crucial to repairing damaged tissue and fighting infection, it can also worsen conditions like rheumatoid arthritis and asthma, and others. It's simply wrong to say it's always good or must always be fought. As Dr. Harriet Hall writes in Science Based Medicine:
It is simplistic to talk of "inflammation" as a single phenomenon, since it is a complex response involving many different physiological processes, from vasodilation to neutrophil infiltration, from the complement system to cytokines. And its relationship to health is even more complex. The human organism is a mesh of interrelated networks, and it could be hazardous to meddle with one element without understanding how our intervention might affect other parts of the system.
When there's a fire, it's soon going to be surrounded with fire trucks. Fire trucks are a city's version of inflammation. When there's a problem, they go there. When the problem's resolved, they go away. It is accurate to say that fire trucks are associated with trouble in the city, just as it is accurate to say that inflammation is associated with many diseases in the body; but leaping to the conclusion that we should be trying to get rid of both is a logical absurdity.
So should we be trying to fight inflammation; and if we did, could we? And would diet be the way to do it? Obviously, anti-inflammatories do, like ibuprofen and a host of others. So it sounds perfectly plausible that some foods may have a similar biochemical effect — and, if you believe the alternative health websites, they do.
Sadly, the scientific evidence is lacking — entirely. No foods have been proven to decrease your body's inflammation or interfere with its natural inflammation processes. However, there is one related diet choice that can: fasting.
When you fast, there's a slight increase of lactic acid in your blood, along with beta-Hydroxybutyric acid, which is associated with ketones. These trigger some chemical reactions that turn off inflammasomes. Another behavior that will do this is exercise. So far as we have evidence for, fasting and exercise are really the only things you can do that will actually retard your body's natural inflammation (short of taking an anti-inflammatory).
If you're looking to food, well then, it's much harder to have any effect, and the only effects available to you are bad ones. Eating a normal amount of any food has not been shown to produce any increase in inflammation. However, overeating — even at a single meal like Thanksgiving when you gorge yourself — will absolutely produce inflammation. If your gigantic meal is high in saturated fats, this effect is greater. The increased inflammation is associated with your body's overdrive effort to metabolize this giant meal, and it subsides once the food has been digested. All of the many related claims made by the alternative health gurus — such as that eating sugar or other particular things will increase inflammation — are only true when those foods are part of your gigantic overeating feast. Therefore, the bottom line on the relationship between diet and inflammation is that there is exactly one, and only one, rule you should follow: Don't overeat.
When you see anything else online, or in a book, or coming from the mouth of your favorite alternative wellness celebrity — no matter how many sciencey-sounding words are in there — be skeptical. The evidence simply doesn't support it. You're naturally omnivorous, and you can relax.
With the possible exceptions of sugar and wheat, the food cited most often by those who embrace these beliefs is processed food. Processed meat, processed cheese, processed sugar, processed anything. This is a good time to insert my periodic reminder that you should nearly always be skeptical when someone speaks of "processed foods" as being a generally bad thing. The reason for this is that rarely in human history has there been a term so uselessly vague. Vilifying a food as "processed" usually means that you don't actually know anything specifically bad to say about it, so you grab the handiest pop-culture buzzword to disparage it for you. Without a doubt, the term "processed food" has a profoundly negative connotation today. But despite what we take it to mean, what does it actually mean?
Processed foods are literally as old as civilization. The original processed foods were cooked meat, bread and cheese, wine and beer. (Five thousand years later, these remain the staples of my diet.) A processed food is any food that has been altered before we eat it: cooking, cutting, juicing, peeling, freezing, dehydration, pasteurization, even packaging. So in point of fact, a piece of uncut, unpeeled fruit or vegetable is about the only unprocessed food that it's possible to get. But in common usage of the term, when people talk about processed foods, they're really referring to prepared foods: foods that have already been combined with other ingredients and prepared before you buy them. And generally, the term is only applied to prepared foods when it's meant in a disparaging way; rarely when the prepared food is perceived by the speaker to be "healthy".
So right away, when you hear someone say "processed foods cause inflammation", they might as well be waving a giant flag saying they don't know what they're talking about.
You're living with inflammation right now. Maybe you're aware of it; probably you're not. It's one of those automated subsystems that your body handles so well. Right now, somewhere inside your body, a small drama is being played out between some damaged tissue or a disease pathogen, and special agents of your body's amazing innate immune system. Inflammation is the packhorse supplying your immune system with whatever it needs from your blood. Let it do what it needs to do. Stop trying to overrule it, just because of some vague falsehoods repeated by a celebrity wellness guru who's only repeating whatever miraculously easy solution they heard from some other celebrity wellness guru. Your immune system knows what it's doing. Leave it alone.
By Brian Dunning
Cite this article:
Dunning, B. "The Inflammatory Diet." Skeptoid Podcast. Skeptoid Media,
13 Mar 2018. Web.
22 Mar 2018. <http://skeptoid.com/episodes/4614>
References & Further Reading
Anft, M. "Understanding Inflammation." Johns Hopkins Health Review. 1 Apr. 2016, Volume 3, Issue 1.
Groopman, J. "Inflamed: The Debate over the Latest Cure-All Craze." The New Yorker. Conde Nast, 30 Nov. 2015. Web. 6 Mar. 2018. <https://www.newyorker.com/magazine/2015/11/30/inflamed>
Hall, H. "Inflammation: Both Friend and Foe." Science-Based Medicine. The Society for SBM, 27 Dec. 2011. Web. 6 Mar. 2018. <https://sciencebasedmedicine.org/inflammation-both-friend-and-foe/>
Kim, E. "Processed Food: A 2-Million-Year History." Scientific American. Nature America, 1 Sep. 2013. Web. 6 Mar. 2018. <https://www.scientificamerican.com/article/processed-food-a-two-million-year-history/>
Lipson, P. "Magic Diet? Not So Much." Science-Based Medicine. The Society for SBM, 23 Jul. 2009. Web. 6 Mar. 2018. <https://sciencebasedmedicine.org/magic-diet-not-so-much/>
Schweitzer, J. "Inflammatory Claims About Inflammation." The Blog. Huffington Post, 28 May 2015. Web. 6 Mar. 2018. <https://www.huffingtonpost.com/jeff-schweitzer/inflammatory-claims-about-inflammation_b_7465534.html>
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