As you likely already know, unless you spent the past week under a rock, or preferably off the grid on a mid-summer idyll, the American Society of Nutrition issued what proved to be a very controversial position paper on processed foods. I know it was controversial because of the media feeding frenzy it induced. My own mid-summer idyll, a scientific conference in Maui with some down time built in for fun with my wife, was interrupted by a number of media requests to react to the ASN paper. My initial comments, for MedPage Today, are found here; I did an interview on Southern California Public Radio (immediately after snorkeling with sea turtles, which I must say I liked better), found here.
The paper in question examined the food sources of key nutrients in the prevailing American diet. The authors noted that a significant percentage of many important nutrients -- including fiber, folate, calcium, and potassium -- were obtained from processed foods. The basic take-away message that resulted, if there is one, is that processed foods are certainly not all bad.
The authors also confronted the challenge of defining "processed," although they did more to highlight the difficulty than resolve it. Freezing is processed, as is cooking. But most of us don't have flash-frozen broccoli, or grilled wild salmon in mind when we talk about "processed" food. There is a legitimate point here that processing occurs on a spectrum, and it's not all bad. But on the other hand, we all knew that already -- and we all knew, more or less, what we meant by "processed." A clear, operational definition of "bad" processing would certainly be helpful. But I suspect that, as famously suggested by Supreme Court Justice Potter Stewart for an entirely different subject, we know what we mean when we see it.
The controversy and media attention engendered by the ASN position paper are, I think, justified. The topic is complicated, the relevant definitions are murky, an assessment of how things are may fail to consider how they really ought to be, and the American Society of Nutrition has important potential conflicts.
Of course processed foods contribute importantly to nutrient intake in the United States, mostly because the typical American diet is overwhelmingly made up of processed foods, many of which are highly fortified (e.g., Total Cereal). Only about 1.5 percent of Americans meet daily recommendations for both vegetables and fruits, so the importance of processed foods to the nutrients we are getting says nothing about where we could, or should be getting those nutrients. Those populations around the world that do derive their nutrients from wholesome foods mostly direct from nature (or nearly so) have much better health to show for it than prevails in the U.S.
The ASN authors provide a service by indicating that an operational definition of processed foods would be quite useful. At the extreme, these are foods that all but glow in the dark. On the other hand, cooking, freezing, drying, and fermenting are clearly forms of 'processing.' As noted, most of us are not referring to grilled salmon, frozen peas, dried figs, or plain organic yogurt when we direct our concerns and invective at processed foods. I have wrestled with this issue myself, albeit from the other direction: what constitutes a legitimately "functional" food? My view is that a multivitamin thrown into a vat of gloop doesn't do it, and is instead the dietary analogue of lipstick on a pig.
As for the ASN position that processed foods make important contributions to the typical American diet, it is to be expected for several reasons. First, because it is true; until the typical American diet improves, processed foods are, indeed, an important source of nutrients. Second, and more concerning, are the entanglements of the ASN with the food industry (a problem it has in common with many other organizations in this space, notably the Academy of Nutrition and Dietetics), deriving much of its financial support from companies that manufacture processed foods. Third, the entire profession of nutrition and dietetics grew out of advances in nutrient biochemistry, hospital-based nutrition, and a focus on the details of nutriture rather than a focus on wholesome foods in sensible combinations per se. The Blue Zones no more attribute their healthful diets to dietitians than to physicians; they owe those benefits to their culture, and a traditional pattern of eating. A nutrient-centric worldview is part of the reason the ASN exists in the first place.
Importantly, though, there are sources without the ASN's conflicts of interest that have taken a similar position. Atlantic author David Freedman wrote a provocative piece suggesting that 'junk' food could be the solution to obesity -- meaning that food could be incrementally improved. I disagreed with him on his choice of words, but not entirely on the position. I believe, as a public health pragmatist, that we will indeed have to trade up processed foods rather than expect to see a sudden, massive shift to produce. On the one hand, we need to trade up our choices enough so they are not just nutrient-fortified junk; on the other, we cannot make perfect the enemy of good. The foodie elite who advocate for utter purity are the modern day equivalents of Marie Antoinette, saying that since the peasants don't have lettuce, they should just eat kale. I think we can, and must, do a whole lot better than that.
The ASN position paper did note that processed foods are major sources of the nutrients we generally get in excess, including sodium, saturated fat, calories, and sugar. That last one is especially noteworthy; processed foods contribute 75 percent of our added sugar (I am a bit surprised it isn't 100 percent, since "adding" sugar should always qualify as "processing" -- but we can let that go). A valid measure of nutritional quality must be holistic, looking at the bad along with the good. What inveighs against the objectionable variety of processed food is the high cost we pay for the nutrients of value it provides, in the currency of calories, sugar, refined starch, salt, and harmful dietary fats along for the ride. In my view, the ASN paper did not do justice to this critical topic.
So, there is a rational argument that we should do the best we can with the food supply we've got, and not make perfect the enemy of good. The benefits that can result from trading up food choices, even if the better choice isn't always organic kale, are quite impressive. But there is, as well, a worrisome aspect to this contention. The defense of processed food is a slippery slope argument that readily devolves into food industry apologism, and the promotion of lipstick-on-a-pig food products.
The ASN position may be controversial particularly because it did not make this distinction emphatically enough. We should certainly do so ourselves, or it won't just be food that is being processed -- but messages about food, and perhaps even those of us eating it.
-fin
David L. Katz, MD, MPH, FACPM, FACP is the founding director of Yale University's Prevention Research Center, President of the American College of Lifestyle Medicine, and author of 'Disease Proof.' He has authored roughly 200 scientific papers and 15 books, including three editions of a nutrition textbook for health care professionals.