Short answer: Whole foods are eaten close to how they grow, like fruit, vegetables, eggs, beans and plain meat. Processed foods have been changed by cooking, canning, freezing or adding ingredients. Processing itself is not the problem: frozen peas and canned beans are healthy. The research concern is ultra-processed foods, which supply about 55% of the calories Americans eat and are linked to weight gain, type 2 diabetes and heart disease.
“Natural vs processed” sounds like good food against bad food, but almost everything we eat is processed in some way. What matters is how much, and why. This guide explains the four levels of processing, with examples of each, what the research actually shows, and how to spot ultra-processed foods on a label.
Whole Foods vs Processed Foods: The 4 Levels of Processing
Researchers usually sort foods with the NOVA system, created by nutrition scientists at the University of São Paulo. It has four groups:
| NOVA group | What it means | Examples |
|---|---|---|
| 1. Unprocessed or minimally processed | Whole foods, or foods only cleaned, cut, dried, frozen, pasteurized or fermented, with nothing added | Fresh and frozen fruit and vegetables, eggs, plain milk, plain yogurt, dried beans and lentils, rice, oats, nuts, fresh meat and fish |
| 2. Processed culinary ingredients | Ingredients pressed, refined or milled from group 1 foods and used in cooking | Olive and vegetable oils, butter, sugar, honey, salt, flour |
| 3. Processed foods | Group 1 foods with a few group 2 ingredients added, usually to preserve them or improve flavor | Canned vegetables and beans, canned fish, cheese, freshly made bread, salted nuts, cured ham |
| 4. Ultra-processed foods | Industrial formulations, made mostly from extracted or modified ingredients and additives you would rarely use at home | Soda, packaged snacks and chips, candy, packaged sweet baked goods, sweetened breakfast cereals, instant noodles, chicken nuggets, hot dogs, many ready meals |
The line between groups 3 and 4 is not always sharp. Bread from a bakery with flour, water, yeast and salt is group 3. Mass-produced sliced bread with emulsifiers and preservatives is group 4. That is why the ingredient list matters more than the type of food.
Examples of Whole, Processed and Ultra-Processed Versions of the Same Food
| Whole or minimally processed | Processed | Ultra-processed |
|---|---|---|
| Corn on the cob | Canned corn | Corn chips, corn puffs |
| Apples | Unsweetened applesauce | Apple-flavored fruit snacks |
| Oats | Homemade oatmeal with a little sugar | Sweetened instant oatmeal packets, cereal bars |
| Chicken breast | Rotisserie chicken | Chicken nuggets |
| Potatoes | Homemade roast potatoes | Flavored potato chips |
| Plain milk | Cheese | Flavored milk drinks, processed cheese slices |
What the Research Shows About Ultra-Processed Foods
- Americans eat a lot of them. A 2025 CDC report found that ultra-processed foods made up 55% of calories for people aged 1 and older, 53% for adults and 62% for children and teens. The biggest sources were sandwiches and burgers, sweet bakery products, savory snacks and sweetened drinks.
- They make it easy to overeat. In a 2019 NIH trial, 20 adults lived at a research center and ate an ultra-processed diet for two weeks and a minimally processed diet for two weeks. The diets were matched for calories, sugar, fat, fiber and salt on offer, and people could eat as much as they wanted. On the ultra-processed diet they ate about 500 more calories a day and gained around 2 pounds. On the minimally processed diet they lost about the same amount.
- Higher intake is linked to several diseases. A 2024 BMJ review pooled 45 meta-analyses covering almost 10 million people. It found the most convincing evidence for links between high ultra-processed food intake and death from heart disease, type 2 diabetes, and anxiety and other common mental health problems.
Two caveats. Most of this evidence comes from observational studies, which show links rather than proof of cause. And ultra-processed foods are a wide category: whole-grain breads and some yogurts can count as group 4, but they do not behave like soda or candy. Most of the risk seems to come from sugary drinks, processed meats and refined snacks. For the official US advice on eating less of these foods, see our guide to the Dietary Guidelines for Americans 2025-2030.
5 Key Differences That Matter for Health
1. Fiber and whole-food structure
Whole foods keep their fiber and cell structure, which slows digestion and helps you feel full. Many ultra-processed foods are soft and quick to eat, so you take in more before fullness catches up.
2. Added sugar, salt and fat
Ultra-processed foods tend to be higher in added sugars, sodium and refined fats. Packaged and restaurant foods supply over 70% of the sodium Americans eat, according to the FDA.
3. How much we eat
As the NIH trial showed, people eat more calories without noticing when most of their food is ultra-processed.
4. Additives
Ultra-processed foods often contain emulsifiers, colors, flavors and preservatives. Additives in the US food supply are permitted as safe at the levels used, but some, like several synthetic food dyes, are being phased out. Animal and early human studies on some emulsifiers and gut health are an active research area, not a settled finding. See how ingredients get approved, including the GRAS loophole.
5. Convenience, cost and safety
Processing is not all bad. Pasteurized milk, frozen vegetables, canned beans and canned fish are safe, affordable and nutritious. Freezing locks in nutrients, and processing lets people eat healthy food out of season and on a budget.
How to Spot Ultra-Processed Foods on a Label
US labels do not say “ultra-processed,” so you have to read the ingredient list and Nutrition Facts label. Signs that a product is ultra-processed:
- A long ingredient list with items you would not cook with at home, such as high-fructose corn syrup, hydrolyzed protein, maltodextrin, dextrose or hydrogenated oils
- Additives that change taste, color or texture: “natural flavors,” artificial flavors, colors, emulsifiers (like soy lecithin, mono- and diglycerides, polysorbate 80), thickeners and gums
- Sugar, or a type of sugar, among the first few ingredients, or several different sugars in one list
- Health claims on the front of a product that is mainly refined flour or sugar. See how labels can mislead.
A “natural” label does not mean a food is unprocessed. The FDA has no formal definition of the word. See what “natural” really means on food labels.
Nutrition or Delicacy: Why Processed Foods Win on Taste
Our taste for sweet, salty and fatty foods helped early humans find energy-rich food when it was scarce. Today that instinct works against us. Many packaged snacks are engineered to hit a “bliss point,” the combination of sugar, fat and salt that makes a food hard to stop eating. That does not mean flavor is the enemy. Food that tastes good is more satisfying, and meals you enjoy are easier to stick with. The goal is to get pleasure from food without relying on excess sugar, sodium and refined fat.
7 Easy Ways to Make Whole Foods Taste Great
- Cook with herbs and spices. Garlic, ginger, cumin, paprika, basil and cilantro add big flavor with almost no calories or sodium. See ginger and cayenne pepper for two easy favorites.
- Roast your vegetables. High-heat roasting caramelizes natural sugars in carrots, Brussels sprouts and sweet potatoes.
- Use healthy fats. A drizzle of olive oil, a few nuts (such as toasted pine nuts) or some avocado adds richness and helps your body absorb fat-soluble vitamins.
- Add acid. A squeeze of lemon or a splash of vinegar brightens flavor so you need less salt.
- Play with texture. Toasted seeds, crunchy greens or a yogurt sauce make simple meals feel more indulgent.
- Choose whole-food swaps. Try fruit with yogurt instead of a pastry, or popcorn instead of chips.
- Keep treats as treats. Build most meals around whole foods and leave some room for favorites in sensible portions.
Simple Swaps for a Healthier Cart
| Instead of | Try |
|---|---|
| Sweetened instant oatmeal packets | Plain oats with fruit and a little honey |
| Soda | Sparkling water with citrus, or unsweetened tea |
| Flavored yogurt | Plain yogurt with fruit or nut butter |
| Packaged snack cakes | Nuts, fruit or popcorn |
| Boxed meals | Home-cooked rice and beans, or a sheet-pan dinner |
| Chicken nuggets | Rotisserie or oven-baked chicken |
Frequently Asked Questions
What is the difference between whole foods and processed foods?
Whole foods are eaten in or close to their natural state. Processed foods have been changed by cooking, canning, freezing, drying or adding ingredients like salt, sugar and oil. Ultra-processed foods go further and are made mostly from industrial ingredients and additives.
Are all processed foods unhealthy?
No. Frozen vegetables, canned beans, canned fish, plain yogurt and cheese are processed and can be part of a healthy diet. The strongest links to poor health are with ultra-processed foods eaten in large amounts.
What are examples of ultra-processed foods?
Soda, chips, candy, packaged cookies and cakes, sweetened cereals, instant noodles, hot dogs, chicken nuggets, and many frozen ready meals and mass-produced breads.
How can I spot ultra-processed foods on labels?
Look for long ingredient lists with items you would not use at home, such as high-fructose corn syrup, hydrogenated oils, flavors, colors and emulsifiers.
Is a whole foods diet healthier?
Diets built mainly on whole and minimally processed foods are consistently linked to better health. You do not need to cut out all processed food. Shifting more of your plate toward group 1 foods is what counts.
The Bottom Line
The useful question is not “is this processed?” but “how processed is it, and what was added?” Build most meals from whole and minimally processed foods, use processed staples like canned beans and frozen vegetables freely, and treat ultra-processed snacks, sweets and sugary drinks as occasional foods.
Sources and Further Reading
- Ultra-processed foods: what they are and how to identify them. Monteiro CA et al. Public Health Nutr. 2019.
- Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial. Hall KD et al. Cell Metab. 2019.
- Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. Lane MM et al. BMJ. 2024.
- Ultra-processed Food Consumption in Youth and Adults: United States, August 2021–August 2023. CDC National Center for Health Statistics, Data Brief No. 536. 2025.
- Sodium in Your Diet. US Food and Drug Administration.
- Dietary Guidelines for Americans. USDA and HHS.
