Ultra-processed foods are designed to be cheap, convenient and irresistible, driving overeating and obesity - and it’s working. Photo / 123rRF
Here’s the most important reason why they’re to blame for obesity and disease.
Ultra-processed foods are all the rage. Over the past several years, they’ve dethroned carbohydrates as dietary enemy number one and are taking the blame for obesity and disease.
And you know what? They deserve that blame, mostly. This is as close to being right as conventional wisdom about diets has ever gotten.
But here’s the thing. Although the conclusion is right, the arguments are mostly wrong. And talking about the wrong things plays right into the hands of the food industry.
So let’s go through what’s wrong, and see if we can’t shift it over to the strong arguments, the right arguments, the arguments that don’t give the food industry a “get out of responsibility free” card.
The wrong arguments are wrong on two fronts: wrong on the evidence that UPFs are bad, and wrong on the reason they’re bad.
Let’s start with the evidence, which comes almost exclusively from epidemiological data - population studies that track people over decades and link their self-reported diet to health outcomes.
You’ll find the data shows, nearly invariably, people who eat lots of UPFs are worse off than people who don’t. In a recent BMJ paper analysing the body of evidence, the authors found UPFs were associated with 32 bad outcomes, including diabetes, heart disease, obesity and all-cause mortality. Also wheezing.
This body of evidence is large, and all I’ve seen points in the same direction. But it’s weak, for two reasons. The first is the same reason that most epidemiological nutrition evidence is weak: the data doesn’t capture the totality of people’s diets (in part, by design, and in part because people aren’t good at remembering and reporting what they eat).
But the second is a problem unique to the UPF controversy: The questionnaires used in these studies don’t ask about degree of processing.
That means to connect the dots between UPFs and health, the researchers have to decide on a definition and then apply it to a list of foods that doesn’t include any information about processing.
One group of researchers tackling the problem wrote a paper about it. They used the Nova definitions (in which UPFs are Category 4 and unprocessed foods are Category 1; Categories 2 and 3 are in-between) and tried to retrofit the questionnaire items into them.
It’s hard! Canned peaches are Category 4, but “other canned fruit” is only a three. Crispbreads are a three, but crackers are a four. Home-made soup is a one unless you use a bouillon cube, in which case it catapults to a four. Salsa is a four, but mustard is a three. Bagels, rolls, brownies, muffins and most other baked goods are fours, but who’s to say you didn’t make them at home, without a bouillon cube?
Big population studies are simply not equipped to tell us much about the link between UPFs and health, but that’s not to say there isn’t one. In all probability, there is, but the question is why.
Frequently, the answer is “processing”, and that’s where we get to the second kind of weak argument. Whether it’s ingredients you can’t pronounce or an industrial production method that pulverises, emulsifies or reconfigures, the theory is there’s something about how our bodies process this food that makes our metabolism go haywire.
The problem is there’s no real evidence to support this idea. Yes pulverised food gets absorbed more quickly; refined carbohydrates, especially when finely ground, raise blood sugar and cause insulin spikes. Nobody thinks that’s optimal (hence the emphasis on whole grains in nutrition advice), but if it were the root cause of obesity and disease, low-carb diets would have a much better track record than they do.
Then there’s the microbiome, which some ingredients in processed food can affect. Problem is, we’re just scratching the surface of how microbiome changes affect our macrobiome (that is, us). While that space is definitely worth watching, none of what we know now comes anywhere close to explaining the many health problems people blame on UPFs.
But if we move beyond metabolism, there’s another possible explanation. It’s got plenty of evidence to support it, and it jibes with everything we know about processed foods. It’s the reason I think processed foods are, indeed, at the root of many health issues. Maybe even 32 of them.
Processing is just a tool. Because food companies are in the business of selling food, they’ve used that tool to give us an endless variety of food we like at affordable prices. They have made it as irresistible as billions of dollars and thousands of food scientists can make it, and they have ensured it’s in front of us all the time, and requires little to no preparation. They’ve advertised and marketed it relentlessly. They have done all of this with essentially no regard for its nutritional content, and they have focused instead on getting us to buy as much of it as possible.
And they’ve succeeded. The problem with UPFs is simply that they drive us to overeat. And it’s weight gain, not preservatives, that poses the health risk.
“You’re just guessing!” I hear you say. “There’s no science to back this up!” I hear you say. I know you’re saying it, because you say it to me on social media all the time.
But you’re wrong. There’s an entire body of science backing this up; it’s just not the science you’re used to looking at to figure out UPFs. It’s the science of how we react to food and food cues in our environment, and it all shows that if food is delicious, convenient, cheap and ubiquitous, we eat more of it.
Well, duh.
Leading off the well-duh cavalcade of research is the simple fact we eat more of food we like. And the efforts the food industry takes to ensure that they’re making foods we really, really like has been extensively documented. If, for some strange reason, you don’t think this is true, pick up Michael Moss’ book Salt Sugar Fat. You will be convinced.
We also eat more when there’s variety, and, well, just look around.
We eat more of foods that are calorie-dense, and ultra-processed foods are more calorie-dense than less-processed foods. (Penn State professor Barbara Rolls has done some of the most interesting research on this issue, and her Wheaties experiment, in which she manipulated energy density by crushing cereal, is one of my all-time favorites.) In the now-famous trial of ultra-processed foods done by the National Institutes of Health’s Kevin Hall, subjects ate about 500 more calories per day of the ultra-processed food, which was more calorie-dense than the minimally processed alternative. (We can’t say for sure the density was the reason, of course, but it’s a prime suspect.)
We eat more of foods that are cheap, and ultra-processed foods, calorie for calorie, are the cheapest out there. We also eat more when food is nearby, and the food industry is all over that, too. And it’s not just the food itself that drives consumption; when we’re exposed to food cues - pictures, videos, ads, smells - we also eat more.
If there were a “CSI: Nutrition”, the prosecutor would be very worried that most of the evidence is circumstantial. And it is! But it is also very consistent, and jibes both with our understanding of how and why we eat, and the epidemiological data. It is the simplest, most straightforward explanation, and it fits all the information we have.
This explanation also puts the food industry on its back foot. If you’re arguing about additives and processes, you’re playing into the industry’s hands, because it will point to the substantial body of evidence on safety, as well as the problems with the epidemiological research. And the industry will have a decent case.
But if the problem really is simply overconsumption, the industry doesn’t have a leg to stand on. Of course, food companies try to make their food irresistible and sell as much as possible! It’s their fiduciary responsibility.
Nevertheless, I expect the steady stream of research about how additives in processed foods can affect our microbiome and our hormones will continue. And it’s good to understand those things! But those are the deck chairs. Iceberg, dead ahead!
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