Are Some Ultra-Processed Foods OK? New Study Has Answers

By Andrea Petersen

A new study is helping to answer a pressing nutrition question: Which ultra-processed foods are harming our health—and which might not be so bad?

The problem is the way many packaged foods are made, researchers believe. Products such as many frozen pizzas, cereals and chips pack more calories per gram than less-processed foods do. And most ultra-processed foods have combinations of salt, fat, sugar and carbohydrates that aren’t generally found in nature, which can make us crave them. Diets high in packaged foods without those traits—such as canned peaches or refried beans—don’t seem to lead people to overeat and gain weight, at least not as much.

Those are the findings so far of a continuing study investigating how ultra-processed food affects our bodies. Scientists presented their interim data at a workshop put on by the National Institutes of Health and the U.S. Food and Drug Administration in December.

“There might be a way to create the quote, unquote healthy ultra-processed food that’s still convenient,” said Kevin D. Hall, the principal investigator of the study and a scientist at the NIH, giving an example of a frozen meal with brown rice, beans and a lot of vegetables.

Ultra-processed foods make up about 58% of the calories that U.S. adults and children ages 1 and older consume in a day, according to an analysis of federal data. Foods are generally considered ultra-processed if they contain ingredients that you wouldn’t find in a home kitchen, such as high-fructose corn syrup and emulsifiers. Yet many scientists believe not all these foods are equally bad—and some might be reasonably healthy.

Recent studies have linked diets high in ultra-processed foods to increased risks of obesity, Type 2 diabetes, cancer, cardiovascular disease and depression. Robert F. Kennedy Jr., the president-elect’s nominee to lead the Department of Health and Human Services, has blamed chemicals and additives in food for widespread health problems.

‘Energy dense’ and ‘hyperpalatable’

When companies make, say, an energy bar, they often break down the cellular structure of the raw ingredients and remove the water, Hall said. Getting rid of water makes sense for food safety, Hall said, since moisture promotes the growth of bacteria.

The process also makes foods more energy dense—meaning they contain more calories per gram than many minimally processed foods do. In the study, the meals with energy-dense foods had about two calories per gram, compared with about one calorie per gram for the meals with fewer energy-dense foods.

In addition, many packaged foods combine fat, sugar, sodium and carbs in ways typically not found in nature. For instance, bagels are usually high in carbs and sodium, muffins are high in fat and sugar, and french fries are high in fat and sodium.

Researchers call these types of foods “hyperpalatable” and they have a strong effect on our brain’s reward system, said Tera Fazzino, associate director of the Cofrin Logan Center for Addiction Research and Treatment at the University of Kansas. This makes it difficult to stop eating them, Fazzino said.

Many seemingly healthy foods are hyperpalatable, including many full-fat flavored yogurts (high fat, high sugar). Salted nuts are hyperpalatable (high sodium, high fat), but plain, unsalted nuts aren’t.

Plain nuts “are good, they are pleasant to consume, but I don’t eat the whole can in one sitting,” Fazzino said.

Preliminary study results and other research suggest that healthier choices for ultra-processed foods include

- Canned peaches

- Canned refried beans

- Canned fruit cocktail

- Jarred salsa

- Low-sodium soups

- Low-fat flavored yogurt

The study

In the current NIH study, 36 participants live for a month at a facility where their meals are tightly controlled. They spend each week on one of four diets. They are offered about 6,000 calories a day and can eat as much as they like.

For one week, they eat minimally processed foods such as plain oatmeal with strawberries and walnuts. For the other weeks, they get versions of an ultra-processed diet.

In one, the meals are energy dense—such as packaged oatmeal with added protein powder, sugar and cream and sweetened cranberries—with most calories coming from hard-to-resist hyperpalatable foods, like honey-roasted peanuts.

In a second ultra-processed diet, meals are energy dense, but fewer calories come from those hard-to-resist foods. The third diet included foods such as scrambled eggs from a liquid egg product with spinach, flavored yogurt and packaged oatmeal with fiber powder and heavy cream. Those meals weren’t energy-dense or hard to resist.

The diets contain roughly the same amounts of calories, fat, sugar, sodium and fiber.

In interim results, which came from 18 people, participants reported feeling just as full and satisfied on all the diets. But when they were on the energy-dense diet with foods such as honey-roasted peanuts, they ate about 1,000 more calories a day than they did while eating the diet with plain oatmeal with strawberries and walnuts.

Not all the ultra-processed diets had such dramatic calorie differences. When people were on the ultra-processed diet that was neither energy dense nor hyperpalatable, they consumed only about 170 calories more a day.

People gained about 1 pound after a week on the energy-dense and hard-to-resist diet. They lost about a half a pound on the minimally processed diet—and also on the one with the liquid-scrambled-egg product.

The findings suggest that eating packaged foods doesn’t automatically result in overeating or weight gain, as long as you stick to foods such as canned refried beans or fruit cocktail, which are low in calories per gram and don’t have the problematic combinations of fat, salt, carbs and sugar.

There are other concerns about convenience foods beyond weight gain. Some of the additives that many contain have been linked to health problems.

What you can do

The NIH research isn’t complete. But its findings so far suggest you can choose healthier packaged foods by checking labels and calculating calories per gram. Avoid foods that clock in at two calories per gram or more, such as frozen meatballs, and stick to those that are around one calorie per gram, like low-fat flavored yogurt.

Or you can combine foods to dilute the overall energy density of your meal, Hall said. Instead of eating chicken fingers with mac and cheese, have them with a big salad.

To avoid hyperpalatable foods, look for products that are low in sodium, Fazzino says. This can include items such as low-sodium frozen meals and soups, she says.

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