What, Exactly, Are Ultra-Processed Foods? And What Role Do They Play in Obesity?

Lately, it seems like everyone is talking about the negative health effects of ultra-processed food. The only surprising thing about this conversation is how long it took for it to happen.

Most Americans now in our 20s through 50s grew up in a culture filled with colorfully flagrant products of ultra-processing—from the brightest Jello and Cheetos and Froot Loops to the whitest Wonder Bread. Kids of the ’80s craved their Hot Pockets and Capri-Suns, kids of the ’90s dreamed of Lunchables and Gushers. (Whether their parents allowed these items into the house was another story.) The ’00s saw the rise of incandescent-yellow Red Bull and countless technicolor energy drinks to follow.

It’s safe to say that nobody’s ever been under the illusion that neon carbonated beverages or day-glo cereals are nutritious. But only recently has it become crystal-clear just how outsized a role the food industry has played in the obesity epidemic. The problem isn’t just that industrially processed foods tend to be high in added sugar, sodium, saturated fat, and carbohydrates, yet simultaneously less filling than whole foods. There are even more insidious ways that faux foods can lead to weight gain, including how they starve our bodies of essential nutrients while hijacking the hormones that control hunger and satiety. And while industrially processed foods used to function mostly as treats or fun school lunches, they’ve gradually gobbled up more and more space in our pantry, fridge, and freezer—in part thanks to more and more ultra-processed foods being marketed as healthy. The result: Ultra-processed food (recently given its own acronym—UPF) now accounts for roughly 60 percent of calorie consumption among U.S. adults, according to the Centers for Disease Control and Prevention (CDC).

In 2025, ultra-processed foods have become so abundant and diverse that it can be confusing to figure out what does and doesn’t fall into that category. A quick primer: The term “ultra-processed foods” was first coined as part of the NOVA food classification system, developed by researchers in Brazil. This classification system sorts all the foods we eat into four groups, as follows:

Group 1 – Unprocessed Foods / Minimally Processed Foods

This group includes foods that have no added ingredients and are consumed in their natural state (or very close to it), like fresh fruits, vegetables, fish, meat, nuts, legumes, eggs, and milk. Minimal processing includes typical home/restaurant food prep like cooking, baking, freezing, drying, and grinding.

Group 2 – Processed Culinary Ingredients

This group includes foods that are primarily used as basic ingredients to be added to other foods, like salt, sugar, butter, and oils.

Group 3 – Processed Foods

These foods are also relatively simple, typically combining two or three ingredients from food groups 1 and 2 using methods that could be achieved in a home kitchen—think canned produce and fish, cheese, jelly, pickles, and fresh-baked bread.

Group 4: Ultra-Processed Foods

Ultra-processed foods are more complex, their ingredient lists filled with additives commonly used in food manufacturing but rarely or never used in home cooking, like preservatives, synthetic vitamins, flavor enhancers, emulsifiers, artificial colors and flavors, and a wide variety of sweeteners. Ultra-processed foods often contain little (if any) intact food from Group 1 of the Nova classification system. Instead, their formulations combine stripped-down food products, food derivatives, and additives. Another way to identify ultra-processed foods is that they tend to have a very long shelf life.