5 facts about ultra-processed foods you should know

When you open a bag of nachos or cheese-flavored chips, you probably know you're about to indulge in an unhealthy snack. Approves? It's the delicious, tangy, cheesy, neon-orange powder that coats every morsel and gets all over your fingers. The same goes for a frozen pizza and chicken nuggets.

But what about a granola bar? A sachet of applesauce? Cheese strips? Flavored yogurt? Surely these foods — snacks that millions of children and adults consume every day — aren't bad, right?

Well, it turns out that many of them fall into the category of ultra-processed foods — depending on its exact ingredients. This type of food has been studied a lot lately, and the results are not good.

Ultra-processed foods represent a relatively new way of categorizing foods. Proposal in 2009 by researchers at USP (University of São Paulo), the system, called NOVA, is not based on the type of food it is — meat, grains, vegetables, etc. — but rather in how processed it is.

NOVA divides foods into four groups, starting with natural and minimally processed foods in the first group, up to ultra-processed foods, which use industrial formulations and manufacturing techniques, in the fourth group.

“My operational definition of ultra-processed foods is that you can't make them in your home kitchen because you don't have the equipment and you don't have the ingredients,” says food policy expert Marion Nestle to the medical correspondent for CNN Meg Tirrell, recently, on the podcast “Chasing Life“. Nestle is the Paulette Goddard Professor Emeritus of Nutrition, Food Studies, and Public Health at New York University.

Ultra-processed foods contain additives like flavor enhancers, colorings, and thickeners — basically ingredients you wouldn't normally use in your cooking. This makes them shelf-stable, easy to prepare (just heat and serve), and, in many cases, hard to resist. (The food industry disputes the NOVA system, saying there is no scientific consensus on the definition of ultra-processed foods).

Due to a confluence of historical, regulatory and economic factors, explains Nestle, food companies in the 1980s “did a lot of studies to find out what combinations of flavor, texture and color would be most attractive to people and began producing foods that would give them a lot of profit.” money”.

She says tens of thousands of new products have hit store shelves since then. “Most of them fail, but the ones that succeed, win big,” Nestle said.

Before you reach for that can of soda, bag of chips or frozen dinner, how about learning more about what you're eating? Here are five things to know about ultra-processed foods:

1. Ultra-processed foods are linked to several diseases

Consuming a lot of ultra-processed foods is not healthy.

“Now there have been more than 1,500 observational studies — all of them demonstrating one consistent finding, which is that eating ultra-processed foods is linked to obesity, type 2 diabetes, heart disease, certain cancers, poor Covid-19 outcomes, overall mortality.” , said Nestle. “Any bad health problem you can think of related to diet is specifically linked to ultra-processed foods.”

The most recent study, published in last Wednesday (8) in the newspaper The BMJ, analyzed more than 30 years of data and found that eating ultra-processed foods was associated with a 4% increased risk of death from any cause, including a 9% increased risk of neurodegenerative death. Other studies have also linked ultra-processed foods to heart disease, type 2 diabetes, cancer and mental health disorders such as anxiety and depression.

Nestle highlighted that these studies were observational and were not designed to prove causality — that is, that ultra-processed foods caused these negative health outcomes.

“You can do this when you have a controlled clinical trial,” she said. “And guess what? We have one.”

2. Ultra-processed foods lead to weight gain

Only one randomized controlled clinical trial showed that ultra-processed foods actually caused people to gain weight.

These types of studies are not easy or cheap to perform, which explains why they are not done more often. To conduct this study, Kevin Hall, a senior researcher at the National Institute of Diabetes and Digestive and Kidney Diseases, had 20 volunteers spend four weeks living at the National Institutes of Health Clinical Center in Bethesda, Maryland, in the United States.

For two weeks, they followed a diet that was 80 percent healthy, ultra-processed foods (think yogurt and whole-grain bread, not chips and soda). For the other two weeks, they followed a diet that did not contain ultra-processed foods. Diets were adjusted for, among other things, calories, sugar, fat, fiber and macronutrients. Participants did not know exactly what the study was measuring.

“We basically asked people to just eat as much of the food as they wanted,” Hall told Tirrell. “You shouldn't be trying to change your weight, (you) shouldn't be trying to gain or lose weight. Just eat at the same appetite level as you normally would.”

The researchers found that when participants were on the ultra-processed diet, they consumed about 500 more calories per day than when they were on the minimally processed diet. This difference in calories was quickly reflected on the scale. Participants gained an average of 2 pounds (about 0.9 kg) during the two weeks on the ultra-processed diet and lost 2 pounds on the minimally processed diet. And their blood tests showed lower markers of inflammation when they were on the second diet.

“If you are not familiar with nutrition research, you have no idea how important this discovery is,” said Nestle, who was not involved in the study. “Five hundred calories is huge.”

Hall said it's not clear what causes people to consume more calories when they're on an ultra-processed diet. “One of the things we’re really interested in now,” he said, “is figuring out what the mechanisms were.”

3. Ultra-processed foods are difficult to avoid

Ultra-processed foods are everywhere, and most of us consume them without even realizing it — even when we think we're eating something relatively healthy, like baked potato chips or a peanut butter and jelly sandwich.

Using data from the National Health and Nutrition Examination Survey, researchers found that ultra-processed foods make up more than half of the diet of American adults. For children in the US, this percentage is even higherreaching 67%.

4. Ultra-processed foods are cheap and convenient

Yes, it's true: Eating “clean” actually costs more.

“To create a minimally processed menu, it cost around 40% more than the ultra-processed menu,” says Hall. “That doesn't even take into account the time it takes to prepare the food, right? So all of these factors probably play a huge role in… the foods we choose to eat in the real world.”

5. Not all ultra-processed foods are bad

Some ultra-processed foods can provide important nutrients, such as whole grain bread and yogurt. And others, in Hall's study, did not increase their caloric intake.

“The snacks were neutral in terms of how many calories (participants) consumed,” Hall said. “Which shows that not all ultra-processed foods necessarily cause this effect.”

Hall's team is conducting a new study to identify which ultra-processed foods are harmful and which are neutral, or even healthy.

Americans may soon receive more help understanding the health effects of ultra-processed foods. The U.S. Department of Agriculture and the U.S. Food and Drug Administration will soon issue new Dietary Guidelines, which are updated every five years. Nestle said the scientific advisory committee guiding this process was asked to consider the connection between ultra-processed foods and negative health outcomes.