Study finds eating ultra-processed foods boosts calories and weight; manufacturers say they make food more affordable

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Kentucky Health News

"Would you eat food that's been pre--digested?"

That's how The Washington Post opened a story that digs deep into how industrial processing changes the structure of food in such a way that it is essentially like eating predigested food. And this, experts say, affects how much we eat, how much our body absorbs, increaring our weight and our risk for chronic disease.

"A growing body of research suggests that the extent of industrial processing that your food undergoes can alter its effects on your body, determining its impact on your appetite, hormones, weight gain, and likelihood of developing obesity and chronic diseases," report Anahad O'Connor and Aaron Steckelberg of the Post. 

Scientists call this type of food u"ltra-processed." The Post offers a detailed example that involves two foods made from corn: canned corn and an ultra-processed snack, corn chips.

The graphics show that by the time both foods go through the packaging process, the canned corn has an "intact food matrix," which means its internal structure, which influences the nutrition provided by the product, remains the same. But the chips have a "broken food matrix," meaning that their nutritional value has been degraded, which affects how our bodies use the food and whether we feel full after eating it.

“Ultra-processing breaks the links between nutrients; it creates new links that our bodies may not recognize, and by doing this it disturbs the digestive process,” Anthony Fardet, a nutrition scientist at the French National Institute for Agriculture, Food, and Environment who studies the effects of food processing on health, told the Post. 

The reporters write that ultra-processed foods make up 58 percent of the calories Americans consume, and that government experts are examining the link between the foods and obesity. Their findings could result in the U.S. following the guidance of countries that have urged people to not eat ultra-processed foods. 

NPR reports that ultra-processed foods make up nearly 70% of what children eat. A separate NPR article notes that "a recent analysis by the Access to Nutrition Initiative finds about 70% of food products sold in the U.S. are unhealthy, and much of the food can be classified as ultra-processed." 

Supporters of the packaged-food industry push back on the idea that ultra-processed foods are bad for you, telling the Post that they are an essential part of the food supply. 

“Processed foods in general help create a more affordable, available, and accessible food environment,” Bryan Hitchcock, chief science and technology officer for the Institute of Food Technologists, told the Post in an email. “Processing technologies, particularly at the industrial scale, add value, safety and nutrition while reducing costs and food loss and waste.”

Chart of Nova analysis for processed foods, from Current Obesity Reports; to enlarge, click on it.

Carlos Monteiro, a nutrition professor at the University of São Paulo, has developed a system to identify ultra-processed foods, called Nova. Its four categories are unprocessed or minimally processed foods, such as an apple; processed culinary ingredients, such as home-baked apples; processed foods, such as packaged applesauce cups; and ultra-processed foods, like packaged apple puff snacks. 

Hitchcock told the Post that not all processed foods are bad for you and that the Nova system "does not capture the nuance" of such foods: "Clarifying which to include more often, and which to reserve for occasional consumption, is essential." Rick Mattes, a nutrition scientist at Purdue University, is a "prominent critic of the Nova system" who says more research is needed before telling people to avoid a broad category of foods, the Post reports. 

The Post also writes about a small study led by Kevin Hall, a nutrition and metabolism scientist at the National Institutes of Health, that recruited 20 men and women to live in a lab and eat a mostly ultra-processed food diet for two weeks, and then a mostly unprocessed food diet for two weeks that was matched for nutrients like salt, sugar, fat and fiber.

The participants could eat all they wanted on both diets. They found that people eating the ultra-processed diet consumed about 500 more calories a day. They also ate the ultra-processed meals faster, at a rate of about 50 calories per minute, compared to 30 calories a minute on the unprocessed diet. 

Those who maintain there is a place for ultra-processed foods in our diets applauded the research, but said more research is needed. 

Allison Aubrey of NPR talked to Dr. Chris van Tulleken, the author of Ultra-Processed People, who made himself a test subject for a one-month experiment that swapped his normal, healthy diet full of non-processed foods to one that mostly came from "packages, boxes and bottles." Tulleken told NPR that about 80% of his calories came from ultra-processed foods during the experiment. 

During the experiment, Tulleken measured his weight and his gut hormones, which send signals to stop eating. He said ultra-processed foods interfere with gut hormones. 

"I became very unwell very quickly. I felt terrible. I stopped sleeping, I developed anxiety and became very unhappy . . . .  So at the end of a meal, my hunger hormones would still be sky high," he said. 

Asked why he thinks the ultra-processed foods left him wanting to eat more, even though he'd had sufficient calories, he first noted that the food is energy dense, so you consume calories at a much higher rate than you would while eating whole foods. 

He also noted that it could because this food "may be being absorbed in a different part of the gut than the part that releases the fullness signal. So I suspect you're eating this food faster than your body's ability to send a signal to the brain saying, 'I'm done now'."

Tulleken told NPR that the U.S. should follow Chile's lead and "put a black hexagon label on the packages of ultra-processed food. So governments shouldn't ban it, or tax the food, because it's the only affordable food for many people. But governments can start to warn people that it has negative health outcomes strongly associated with it." 

The New Yorker also took a deep dive into Tulleken's book. Writer Adam Gopnik notes, "The book isn’t just a chronicle of his diet-induced damage; page after exhausting page is given over to the foundations of nutritional science." 

The Economist also writes about the issue, pointing out that Tulleken draws a distinction between ultra-processed food and processed food, while noting that almost everything people consume is processed in some form. Further, The Economist writes that Tulleken points out that the "cocktail of additives and preservatives in ultra-processed foods harm people in ways both known and unknown."