Ultra-processed foods are everywhere. How bad are they?

Whether they know it or not, most Americans don't go a day, or even a meal, without eating ultra-processed foods.

From sugary breakfast cereals to frozen pizzas for dinner to snacks like potato chips, soda, and ice cream, ultra-processed foods make up about 60 percent of the U.S. diet. For children and teenagers, the percentage is even higher, making up about two-thirds of what they eat.

This is concerning because ultra-processed foods have been linked to a range of negative health effects, from obesity and diabetes to heart disease, depression and dementia, and recent studies suggest that eating these foods may increase your risk of premature death.

But nutrition science is tricky, and most studies to date have found associations, rather than evidence, about the health effects of these foods.

Food manufacturers argue that processing improves food safety and supply, and makes diverse, nutritious meals cheaper and more convenient.

Even if the science was clear, it's hard to know what practical advice to give when one study estimates that ultra-processed foods make up 73 percent of the U.S. food supply.

When the Associated Press asked several nutrition experts, here's what they said:

Most foods are processed through methods such as freezing, grinding, fermentation, and pasteurization. In 2009, Brazilian epidemiologist Carlos Monteiro and his colleagues wrote: system It classifies foods according to their degree of processing rather than their nutritional value.

At the top end of the four-point scale are foods made using industrial processes with additives, colors, preservatives and other ingredients that can't be replicated in a home kitchen, said Kevin Hall, a researcher working on metabolism and diet at the National Institutes of Health.

“These are most of the packaged foods you see, but not all of them,” Hall says.

Dr. Neena Prasad, director of the food policy program at the Bloomberg Charitable Foundation, said these foods are often made to be cheap yet highly tasty.

“It has just the right balance of sugar, salt and fat, and I can't stop eating it,” Prasad says.

But Hall points out that processing alone doesn't determine whether a food is unhealthy: whole wheat bread, yogurt, tofu and infant formula, for example, are all highly processed but also highly nutritious.

Here's the tricky part: Many studies suggest that diets high in these foods are bad for your health, but they don't tell us whether the foods are causing the effects, or whether something else about the people who eat them is to blame.

At the same time, ultra-processed foods overall tend to be higher in sodium, saturated fat and sugar and lower in dietary fiber and protein, and it's not clear whether these nutrients are the only contributing factors.

Hall and his colleagues conducted the first small but influential study to directly compare the outcomes of consuming similar diets of ultra-processed and unprocessed foods.

Published in 2019The study involved 20 adults who stayed at the NIH center for a month and were asked to eat as much as they wanted for two weeks on a diet that included ultra-processed and unprocessed foods that were matched for calories, sugar, fat, fiber and macronutrients.

The researchers found that participants who followed the ultra-processed diet ate about 500 more calories per day than those who ate whole foods and gained an average of about 2 pounds (1 kilogram) in weight over the study period, compared with about 2 pounds (1 kilogram) lost during the same period when they ate only whole foods.

Hall is currently conducting a more detailed study, a lengthy and expensive process that won't yield results until late next year, but he and his colleagues say such definitive studies are needed to determine exactly how ultra-processed foods affect consumption.

“If it's causing adverse health effects, it's better to understand the mechanism,” he said.

Some advocates like Prasad argue that the mountain of research linking ultra-processed foods to health harms is more than enough to spur government and industry to make policy changes. She calls for measures like higher taxes on sugary drinks, tougher sodium limits for manufacturers and a crackdown on the marketing of such foods to children in the same way that tobacco marketing is curbed.

“Do we want to risk our kids getting sick while we wait for the perfect evidence?” Prasad says. Earlier this year, FDA Commissioner Robert Califf addressed the issue, telling a food policy panel that ultra-processed foods were “some of the most complicated things I've ever dealt with.”

But, he concluded, “We have to have the science and we have to implement it.”

Aviva Musicas, science director at the Center for Science in the Public Interest, which promotes food policy, said highly processed foods are hard to avoid in a country like the United States, and it's not clear which foods should be targeted.

“The range of ultra-processed foods is really wide,” she says.

Instead, it's better to pay attention to the ingredients in your food – check the labels and choose what fits. Current U.S. Dietary Guidelinesshe suggested.

“There's strong evidence that added sugar is bad for you. There's strong evidence that high-sodium foods are bad for you,” she says. “There's also strong evidence that minimally processed fruits and vegetables are good for you.”

It's important not to blame specific foods, she added, as many consumers don't have the time or money to cook most of their meals from scratch.

“I believe food should be fun and delicious and shouldn't involve moral judgment,” Musicas said.

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute's Science Education Media Group. The AP is solely responsible for all content.