Ultra Processed Food: What Counts and Why It Matters

"Ultra processed" has become one of the most used phrases in nutrition. It is also one of the most misunderstood. Frozen broccoli is processed. So is a block of cheese. Neither is what researchers mean by the term.

The plain definition

Researchers sort food into four groups by how much it has been changed from its original form.

• Whole or minimally processed: fruit, vegetables, eggs, meat, fish, plain yogurt, rice, dried beans, frozen vegetables.
• Cooking ingredients: oils, butter, salt, sugar.
• Processed foods: simple combinations of the first two, like cheese, canned beans, canned fish and fresh bread.
• Ultra processed foods: products built mostly from refined pieces of food, such as starches, isolated proteins, refined oils and sugars, plus additives you would not find in a home kitchen. Emulsifiers, flavorings, colors and sweeteners are common examples.

A quick test is the ingredient list. If it reads like a recipe you could make, the food is probably processed. If it includes several items you could not buy at a grocery store, it is probably ultra processed. Soda, most packaged snacks, sweetened cereals, packaged pastries, instant noodles and many frozen meals fall here. In the US, these foods make up more than half of the calories adults eat.

Why it matters

The strongest evidence comes from a small but tightly controlled feeding study of 20 adults at the National Institutes of Health. Adults lived in a research unit for four weeks. For two weeks they were offered an ultra processed diet, and for two weeks a minimally processed one. Both diets were matched for calories, sugar, fat, fiber and salt on the plate, and people could eat as much as they wanted.

On the ultra processed diet, people ate roughly 500 more calories a day and gained weight. On the minimally processed diet, they ate less and lost weight. They also ate the ultra processed meals faster.

That speed is likely part of the reason. These foods are soft, easy to chew and dense in calories. Fullness signals from the gut take time to reach the brain, and when food goes down quickly, more of it is eaten before those signals arrive. Many of these products are also low in protein and fiber, the two things that keep people full longest.

Easy swaps

You do not need to remove every packaged food. Start with the ones you eat most often.

• Sweetened cereal to oats with fruit, or eggs.
• Chips to nuts, or popcorn you make at home.
• Flavored yogurt to plain Greek yogurt with berries.
• Packaged deli meat to chicken you cook in a batch on Sunday.
• Soda to sparkling water.

A few swaps in the foods you eat every day will do more than a perfect week followed by a return to old habits.

The most useful plan is one built from your own numbers and your own grocery list. That's what we build in the nutrition program.

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This article is educational and is not medical advice.