Whether they know it or not, most Americans don’t go a day (and often a single meal) without eating ultra-processed foods.
From sugary cereals for breakfast to frozen pizzas for dinner, plus snacks on chips, soda and ice cream, Ultra-processed foods account for approximately 60% of the American diet. In the case of children and adolescents, the proportion is even higher: approximately two-thirds of what they eat.
This is worrying because ultra-processed foods have been linked to a range of negative health effects, from obesity and diabetes to heart disease, depression, dementia and more. A recent study suggested that eating these foods may increase the risk of premature death.
However, the science of nutrition is complicated, and most research so far has found connections, not evidence, regarding the health consequences of these foods.
Food manufacturers argue that processing improves food safety and supply and offers a cheap and convenient way to provide a varied and nutritious diet.
Even if the science were clear, it’s hard to know what practical advice to give when ultra-processed foods account for what one study estimates to be 73% of the U.S. food supply.
What are ultra-processed foods?
Most foods are processed, whether by freezing, grinding, fermentation, pasteurization or other means. In 2009, Brazilian epidemiologist Carlos Monteiro and his colleagues first proposed a system that classifies foods based on the amount of processing they undergo, not their nutrient content.
At the top of the four-tier scale are foods created through industrial processes and with ingredients such as Additives, colorants and preservatives that couldn’t be duplicated in a home kitchen, said Kevin Hall, a researcher who focuses on metabolism and diet at the National Institutes of Health.
These are most, but not all, of the packaged foods we see,” Hall said.
These foods are often crafted to be cheap and irresistibly delicious, said Dr. Neena Prasad, director of Bloomberg Philanthropies’ Food Policy Program.
“They have just the right combination of sugar, salt and fat and you can’t stop eating them”Prasad said.
However, the level of processing alone does not determine whether a food is unhealthy or not, Hall said. Whole-grain bread, yogurt, tofu and baby formula are all highly processed foods, but they are also nutritious.
Are ultra-processed foods harmful?
Here comes the tricky part. Many studies suggest that diets high in these foods are linked to negative health outcomes. But these types of studies can’t say whether the foods are the cause. the negative effects or if there is something else in the people eating these foods that could be responsible.
At the same time, ultra-processed foods, as a group, tend to have higher amounts of sodium, saturated fat and sugar, and tend to be lower in fiber and protein. It’s not clear whether it’s just these nutrients that are driving the effects.
Hall and his colleagues were the first to conduct a small but influential experiment that directly compared the results of eating similar diets composed of Ultra-processed vs. unprocessed foods.
Published in 2019, the research involved 20 adults who went to live at an NIH facility for a month. They were given diets of ultra-processed and unprocessed foods with the same calories, sugar, fat, fiber and macronutrients for two weeks each and were told to eat as much as they wanted.
Researchers found that participants who ate a diet of ultra-processed foods consumed about 500 more calories per day than when they ate unprocessed foods, and gained an average of 2 pounds (1 kilogram) over the study period. When they ate only unprocessed foods during the same time period, they lost about 2 pounds (1 kilogram).
Hall is conducting a more detailed study, but the process is slow and expensive, and results are not expected until late next year. He and others say such definitive research is needed to determine exactly how ultra-processed foods affect consumption.
“It is better to understand the mechanisms by which harmful health consequences are generated, if they are generated,” he said.
Should ultra-processed foods be regulated?
Some advocates, like Prasad, argue that the wealth of research linking ultra-processed foods to poor health should be more than enough to prompt the government and industry to change their policies. She calls for actions such as raising taxes on sugary drinks, imposing tighter sodium restrictions on manufacturers and ending advertising of such foods to children, in the same way tobacco advertising is limited.
“Do we want to risk making our kids sicker while we wait for these perfect tests to come along?” Prasad asked. Earlier this year, FDA Commissioner Robert Califf addressed the issue, telling a conference of food policy experts that ultra-processed foods are “one of the most complex things I’ve ever dealt with.”
But, he concluded, “we have to have the scientific basis and then move forward.”
How should consumers handle ultra-processed foods at home?
In countries like the United States, it’s hard to avoid highly processed foods, and it’s not clear what the goal should be, said Aviva Musicus, science director at the Center for Science in the Public Interest, which advocates for food policy.
“The range of ultra-processed foods is very wide,” he said.
Instead, it is better to pay attention to the ingredients in foods. Check labels and choose options that fit to current dietary guidelines from the US, he suggested.
“We have very strong evidence that added sugar is not good for us. We have evidence that high-sodium foods are not good for us,” she said. “We have strong evidence that minimally processed fruits and vegetables are actually good for us.”
It’s important not to denigrate certain foods, she added. Many consumers don’t have the time or money to cook most meals from scratch.
“I believe that meals should be joyful and delicious and should not involve moral judgments,” Musicus said.
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