The Mounting Evidence Against Ultra-Processed Foods

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Recent research has linked diets that include a lot of foods considered “ultra-processed”—such as soft drinks, instant soups, and chicken nuggets—to an increased risk of obesity, high blood pressure, irritable bowel syndrome, and even cancer. Now, two new studies published in the British Medical Journal find a link between high consumption of these foods and risk of both cardiovascular disease and early death.

Both studies are observational, which means they can’t directly prove a cause and effect. But evidence is growing that ultra-processed foods can hurt your health, says Mark Lawrence, Ph.D., professor of public health nutrition at Deakin University in Australia, who wrote an editorial accompanying both studies.

What the Studies Found

For both studies, researchers used a food classification system, developed by Brazilian scientists, called NOVA. This system breaks foods down into four categories:

• Unprocessed foods such as fruits; veggies; legumes; milk; eggs; meats; poultry; seafood; fermented milk, like yogurt; whole grains; natural juice; coffee; and water.

• Processed cooking ingredients, such as salt, sugar, honey, vegetable oils, butter, and lard.

• Processed foods, such as condensed milk, cheeses, cured ham, canned fruit, bread, beer, and wine.

• Ultra-processed foods—ones that contain ingredients that you wouldn’t cook with, such as colorings, anti-caking agents, and emulsifiers. “Anything with a long list of ingredients, including additives, is suspect,” Lawrence says. Examples include packaged baked goods like cookies and croissants, sugary cereals, ready-to-eat meals that contain food additives, instant soups, and processed meats such as salami and hot dogs.

In the first study, researchers had more than 105,000 French middle-aged adults fill out six 24-hour dietary questionnaires. They found that for every 10 percent of a respondent’s diet that was made up of ultra-processed foods, there was just over a 10 percent increase in rates of heart disease, cardiovascular disease, and cerebrovascular diseases such as stroke. The more unprocessed or minimally processed foods they ate, the lower their risk.

In the second study (PDF), researchers had almost 20,000 Spanish university graduates complete a 136-item dietary questionnaire. They found that those who consumed more than four servings a day of ultra-processed foods had a 62 percent greater risk of death during the study period than those who ate less than two servings a day. Each serving of ultra-processed food raised risk of dying by 18 percent.

Researchers don’t know exactly why ultra-processed foods may cause health problems. “They are often high in saturated fat, calories, sugar and salt, and low in key nutrients like fiber,” says Mathilde Touvier, Ph.D., nutritional epidemiologist with the Sorbonne Paris Cité Center of Research in Epidemiology and Statistics Research and co-author of the French study. “But we also think it’s due to the wide range of chemicals and additives found in these, foods, ranging from acrylamide, a cancer-causing chemical created when heating processed foods, to the bisphenol A found in a product’s packaging.”

But trying to whittle down which ingredients are harmful is pointless, Lawrence says. “Rather than trying to reformulate these packaged foods to make them safer, we should be directing our efforts to making sure unprocessed or minimally processed foods are affordable and available.”

Another problem with ultra-processed foods is that people tend to overeat them, and thus gain weight. A recent study published in the journal Cell Metabolism found that subjects who ate an ultra-processed diet ate about 500 calories more per day than those whose diet was rich in whole foods. “These foods are often filled with added sugars, salt, refined carbohydrates, and fat,” says David Katz, M.D., M.P.H., director of the Yale-Griffin Prevention Research Center in Derby, Conn. “The study itself found that people who ate ultra-processed foods tend to eat them faster and that they had lower levels of appetite-suppressing hormones than those who ate whole foods. As a result, they may have ended up eating more in order to feel satisfied.”

How to Eat More Whole Foods

About 60 percent of Americans’ total daily calories come from ultra-processed food, according to study researchers, so there is room for improvement. “It’s not that you have to cut them out of your diet completely—it appears that health risks start cropping up once you begin eating more than two servings a day,” Lawrence says. “Like everything else in life, it’s about moderation.” Here are five easy ways to reduce your intake.

Read ingredient lists carefully. The shorter, the better. Avoid anything that contains hydrogenated oils, artificial flavors, or strange-sounding substances you don’t recognize that the manufacturer says are put there to maintain freshness. “All the ingredients should look like something you could make in your own kitchen,” Katz says. This is true even if it’s a seemingly healthy staple such as an energy bar, a protein shake, or even a plant-based milk drink. These have all gotten a health halo though they can be ultra-processed foods, says Julie Stefanski, R.D.N., a nutritionist in Morrisville, N.C., and spokesperson for the Academy of Nutrition & Dietetics.

Make it yourself. It can be easier than you think to whip up your own staple items. “It takes less than a minute to stir together a salad dressing with ingredients you have on hand, such as olive oil, balsamic vinegar, and herbs and spices,” Stefanski says. Instead of spending money on a premade protein shake, create your own with low-fat milk, frozen fruit, and a tablespoon of natural nut butter. Instead of a sugary fruit-flavored yogurt, opt for the plain variety and sweeten it with fruit.

Shop smartly. When you hit the supermarket, focus on the perimeter. That’s where most of the unprocessed fare—think produce, legumes, nuts, dairy, meat, and fish—are located. Don’t shy away from canned or frozen fruits, veggies, broth, or meats, either. Although these are considered “processed” foods, they weren’t associated with any increased risk of death or disease, Lawrence says.

Skip creams and sweeteners in your coffee or tea. Most powdered and flavored liquid creams are simply dried high-fructose corn syrup, Stefanski says. Lighten your drink with a splash of milk instead.

Plan snacks in advance. Most of the time, we reach for processed foods because it’s convenient. Carry snacks such as homemade trail mix or fruit with nut butter with you, so you can nosh when hunger hits instead of attacking the vending machine.

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