We eat a lot of ultra-processed food. It’s everywhere, and the cheapest grocery options are often ultra-processed ones. That’s why it’s concerning that ultra-processed foods have been linked to a variety of health problems, including heart disease, diabetes, mental health disorders, and everyone’s favorite, all-cause mortality. So what counts as ultra-processed food? Let’s dig in, and maybe question a few assumptions along the way.

Here’s a big caveat worth remembering: When studies look at the health of people who do and don’t eat ultra-processed foods, they’re not necessarily studying the fact that the food is ultra-processed. We can say that a diet high in candy bars is bad for us, but is that because the candy bars are ultra-processed, or because they’re full of sugar? That’s not a question that the current research can really untangle, but it’s important to ask ourselves as we learn more. Are ultra-processed foods always bad, or are they just a category that includes a lot of food we should eat less of?

How are ultra-processed foods defined?

This terminology comes from a classification scheme called NOVA that splits foods into four groups:

Unprocessed or “minimally processed” foods (group 1) include fruits, vegetables, and meats. Perhaps you’ve pulled a carrot out of the ground and washed it, or killed a cow and sliced off a steak. Foods in this category can be processed in ways that don’t add extra ingredients. They can be cooked, ground, dried, or frozen.

Processed culinary ingredients (group 2) include sugar, salt, and oils. If you combine ingredients in this group, for example to make salted butter, they stay in this group.

Processed foods (group 3) are what you get when you combine groups 1 and 2. Bread, wine, and canned veggies are included. Additives are allowed if they “preserve [a food’s] original properties” like ascorbic acid added to canned fruit to keep it from browning.

Ultra-processed foods (group 4) don’t have a strict definition, but NOVA hints at some properties. They “typically” have five or more ingredients. They may be aggressively marketed and highly profitable. A food is automatically in group 4 if it includes “substances not commonly used in culinary preparations, and additives whose purpose is to imitate sensory qualities of group 1 foods or of culinary preparations of these foods, or to disguise undesirable sensory qualities of the final product.”

That last group feels a little disingenuous. I’ve definitely seen things in my kitchen that are supposedly only used to make “ultra-processed” foods: food coloring, flavor extracts, artificial sweeteners, anti-caking agents (cornstarch, anyone?) and tools for extrusion and molding, to name a few.

Are ultra-processed foods always bad?

So we’ve learned that packaged snack cakes are ultra-processed, and so is a factory-baked loaf of bread that has 20 ingredients. Orange juice whose flavor has been manipulated would count, too. Coke and Diet Coke are both solidly in this category. It seems logical that we should eat less of these things.

But you could argue that the real problem with these foods is that they’re often sugary and high calorie, and many of the less-healthy members of the category are what stock the vending machines and convenience stores that beckon to us when we’re hungry and haven’t packed a lunch. The problem with these foods is that a diet full of them is unbalanced, due to the nutrition they do or don’t contain. The processing itself isn’t the problem.

So when we talk about ultra-processed foods, we have to remember that it’s a vague category that only loosely communicates the nutrition of its foods. Just like BMI combines muscley athletes with obese people because it makes for convenient math, NOVA categories combine things of drastically different nutritional quality.

Why the level of processing isn’t always the most important thing

Illustrating the point above, the USDA published their own study showing how you can create a healthy diet out of ultra-processed foods. A homemade breakfast burrito, for example, might contain canned beans, liquid egg whites, shredded cheese, and a store-bought tortilla. Those ingredients might be ultra-processed, but they’re nutritionally nothing like grabbing a Cinnabon on your way to work.

A pet peeve of mine is that the NOVA classification sometimes draws distinctions between things that aren’t really nutritionally different. Wine is in group 3 next to cheese and fresh bread, but cocktails are in group 4 with the Twinkies. Hard liquor has been distilled, you see, so it’s ultra-processed.

Canned vegetables are in group 3 (processed) while their fresh counterparts are in group 1. But canned veggies aren’t any less nutritious. Meanwhile, dried fruit is in group 1 (so wholesome!) even though it can be more sugary than cakes or cookies.

There’s a lot of overlap between unhealthy(?) foods and ultra-processed foods, so I understand why scientists are studying ultra-processed foods as a group. But demonizing UPF, as they’re sometimes called, often ends up putting the cheapest, most widely available food in the most shameful category. Is that fair, or does it just make you feel better when you’re eating fresh green beans and scoffing at people who buy canned?

The NOVA scale isn’t totally useless: It helps researchers keep an eye on how much of our food is coming from large-scale manufacturers. But it’s not a great way to evaluate what’s in our grocery bags, or on our plates.