What happened when ultra-processed foods were matched for calories, sugar, fat, and fiber content in the first randomized controlled trial?
In the United States, “junk food” is often used to describe less-healthy foods, like candy, ice cream, and chips, but there isn’t a consistent definition, so nutrition researchers came up with the concept of ultra-processed.
The term “ultra-processed food”—if you want to call it that—describes industrial formulations that are typically seen in those long list of ingredients, which, besides salt, sugar, and fat, aren’t typically found in any cookbook, like various flavors, sweeteners, colors, emulsifiers, and other additives used to imitate real foods or to hide undesirable qualities of the final product. This roughly corresponds to my idea of “red light foods” in my traffic light system, in which, ideally, we should maximize intake of green light foods, minimize yellow light foods, and avoid red light foods. Indeed, most of what people eat are red light foods: soda, ice cream, candy, cakes, most bread and breakfast cereals, TV dinner-type ready-to-heat products, chicken nuggets, fish sticks, sausages, burgers, and hot dogs. There has been a dramatic rise in ultra-processed foods. In fact, the U.S. food supply is dominated by them. More than 200,000 products were assessed, and 71% were classified as ultra-processed.
And, of course, they aren’t only in grocery stores. Sugary drinks and processed junk are ubiquitous even at non-food retailers, sending pervasive cues to consume products that are dense in calories but poor in nutrition. As a former head executive of Coca-Cola put it, the soda should be kept within an “arm’s reach of desire.” A major candy brand boasted, “We put them everywhere: grocery stores and supermarkets, gas stations and chiropractors’ offices, bowling alleys and grocery stores, which we already mentioned. Not sorry.”
So, this is where we are today. What proportion of food consumed by U.S. children and adolescents is classified as junk? An unbelievable 56% to 70% of what our children and teens eat over the entire day is junk. But kids will be kids, right? In the United States, more than half of the calories taken in across the board are junk. In fact, around the world, ultra-processed foods consistently account for more than 50% of the dietary caloric intake in the higher-income countries. No wonder unhealthy diets are humanity’s greatest killer, the leading risk factor for death globally, as you can see below and at 2:25 in my video Ultra-Processed Junk Food Put to the Test.
What exactly are the health consequences? The biological effects of modern foods have been studied using rats, showing they gorge themselves into dramatic weight gain, inflammation, and cognitive and metabolic abnormalities. And just as ultra-processed foods were taking over, binge eating was recognized as a new eating disorder, and it grew into the most common form of eating disorder. And not surprisingly, binge foods were found to be 100% ultra-processed. That’s no surprise—these foods are engineered so you can’t have just one. People don’t tend to binge on broccoli.
About 9 out of 10 studies found that ultra-processed food consumption was associated with adverse health outcomes—and not just obesity, but cancer, cardiovascular diseases, type 2 diabetes, irritable bowel syndrome, depression, frailty, and all-cause mortality (meaning living a shorter life). Studies on youth add asthma to the list and also report higher DNA damage. Not a single study reported a link between ultra-processed foods and beneficial health outcomes.
In contrast, populations with low meat consumption, high fiber intake, and low intake of minimally processed foods have far fewer chronic diseases, enjoy lower obesity rates, and live longer disease-free. But most of the findings were based on observational studies. You don’t know for sure if ultra-processed foods themselves are to blame until you put it to the test.
In the first randomized controlled trial on ultra-processed foods, 20 people were essentially locked in a hospital ward and received both ultra-processed and unprocessed diets for 14 days each. Here’s the kicker: The diets were designed to provide the same calories, sugar, fiber, fat, and macronutrients. Why? In response to criticism, manufacturers are now proposing reformulating their products, keeping them ultra-processed but tweaking them by adding some fiber, for instance, or reducing the sugar, fat, or salt. So, the researchers wanted to try to tease out the effect of ultra-processing by giving the study participants the same amount of calories, sugar, fat, fiber, carbs, and protein in each of the two diets. So, for instance, for breakfast in the ultra-processed weeks, the participants would get Cheerios and a muffin, or an egg and cheese muffin with turkey bacon and orange juice. When it was time for the less-processed breakfasts, people would get, say, oatmeal with blueberries and almonds. The meals had the same amount of overall sugar and fat, but the unprocessed option was presented more in whole food form. For lunch, the ultra-processed group might get a turkey sandwich with nonfat Greek yogurt, canned peaches, baked potato chips, and sugar-free Crystal Light Lemonade, versus a Southwest entrée salad with black beans, carrots, corn, avocados, and nuts, along with grapes and apples on the unprocessed diet. The same calories were offered, with the instruction to eat as much or as little as they wanted.
So, what happened? On the ultra-processed diet, people ate about 500 more calories a day and, unsurprisingly, gained about two pounds on the processed diet, or actively lost two pounds on the less-processed diet, as you can see below and at 5:31 in my video.
So, the problem wasn’t just the unbalanced nutrient profile of ultra-processed foods. Simply tweaking them wouldn’t magically make them healthy, but that’s what the industry would rather do. Reformulation is referred to as the “unobtrusive strategy,” creating “the prospect of nutritional improvement without dietary change.” But what this study showed is that it may be better to limit the consumption of ultra-processed foods altogether.
Why does the industry love them so much? They’re made with dirt-cheap ingredients, like taxpayer-subsidized corn syrup, allowing for huge corporate profit margins. But at what cost? The food industry takes in more than a trillion dollars every year, yet most of our healthcare dollars go to treat chronic diseases exacerbated by these very same foods, like diabetes and heart disease. So, you could argue “we lose triple what the food industry makes.” The food industry argues that these days, it’s “unrealistic” to tell people to avoid ultra-processed food, given societal time constraints and the difficulties of food prep, but this may just be acquiescing to the same propaganda and disinformation campaign that the processed food industry has used to co-opt families for decades. Those who think healthy foods can’t be convenient have never met an apple.
That was a response to Dr. Lustig’s essay on processed food as a failed experiment, in which he said: “One-third of American mothers today don’t even know what real food is or how to cook; they and their children are destined to remain hostages to the processed food industry.” I don’t like his mother-blaming, but I do appreciate his prescription: “There’s only one recourse—real food, which is low in sugar and high in fiber.” We need to start thinking outside the box.
Doctor’s Note
It’s no surprise processed foods are wreaking havoc on our health. Learn about The Role of Processed Foods in the Obesity Epidemic. Is there a solution? Yes. Cut the Calorie-Rich-And-Processed Foods.
This is the third video in a series on junk food. If you missed the first two, check out Do Healthy Fast Food Options Lead to Healthier Choices? and How We Won the Fight to Ban Trans Fat.
I mentioned my traffic light system for choosing the healthiest foods. Learn all about it in Dining by Traffic Light: Green Is for Go, Red Is for Stop.