What Are Processed Foods?

Processed foods are any foods that have been altered from their original state, but the level of processing can vary widely. Food is processed to extend its shelf life, enhance its palatability, texture, or nutritional makeup.

It’s important to know that a food is not automatically harmful to health just because it’s processed. Processing can make food easier to transport, enhance the nutritional value of an otherwise nutrient-poor food, or improve safety by eliminating harmful microorganisms that can cause illness.

For example, frozen vegetables are a processed food that is flash frozen at peak ripeness, preserving their nutrients.

Currently, the NOVA classification system categorizes foods into different levels of processing and breaks foods into four groups: ^[1] Braesco V, Souchon I, Sauvant P; Ultra-processed foods: how functional is the NOVA system? Eur J Clin Nutr. 2022;76:1245-1253. doi:10.1038/s41430-022-01099-1.

Group 1: Unprocessed or Minimally Processed Food

Whole foods typically found in the perimeter of the grocery store, including meat, poultry, fish, fresh and frozen fruits and vegetables, milk, and eggs.

Group 2: Processed Culinary Ingredients

Ingredients commonly added to foods in the kitchen, like plant oils, butter, sugar, salt, and honey. These undergo some level of processing to preserve their freshness and reduce the risk of rancidity (especially in the case of fat-containing oils).

Group 3: Processed Foods

Minimally processed foods with added ingredients, such as salt, sugar, butter, or oil. Because of these added ingredients, they are considered more processed than Group 1 and 2 foods, but still contain only a few ingredients. These include bread, jam, salted nuts or seeds, frozen vegetables with salt or added sauces, canned fish, and cured meats such as bacon and salami.

Group 4: Ultra-processed Foods

These foods are primarily made from more refined industrial food ingredients and contain preservatives, additives, colors, and flavors. They may or may not contain high amounts of sodium, saturated fat, or added sugar, and often contain a longer list of ingredients. Examples include potato chips, sugary cereals, soda, frozen pizza, instant noodles, and fast food. 

However, while many foods in this category are more clearly designated as unhealthy processed foods,  this category also includes more seemingly healthy foods such as sweetened yogurts, protein powders, and even certain peanut butters.

This is where the classification can get a bit dicey, as some protein powders, yogurts, and peanut butters contain minimal ingredients, while others may be packed with questionable emulsifiers, added sugar, or artificial sweeteners that require a higher level of processing.

While this is the current classification method, many health experts are exploring more accurate ways to classify foods that reflect their true health profile, rather than just focusing on the number of ingredients or degree of processing.

How Ultra-Processed Foods Affect Your Health

While all foods exist on a spectrum of processing, it’s the ultra-processed foods that pose the greatest health risks. When consumed in excess, these processed food health risks include insulin resistance and type 2 diabetes, impaired gut health, weight gain, and more. ^[2] Ultra-processed foods? Just say no. Harvard Health. Published June 17, 2024.

The biggest culprits, however, aren’t items like plain nut butters or protein powders, which can still offer nutritional value as part of a healthy diet, but rather heavily engineered foods with added sugar, saturated fat, and sodium. These include cookies, potato chips, candy, sugary breakfast cereals, frozen pizza, fast food, and sweetened beverages like soda and juice.

While it is perfectly fine to enjoy your favorite frozen pizza on a Friday night, these foods should be limited in the diet. This is especially important when these foods may replace more nutritious whole or minimally processed foods, which can increase the risk of the following issues.

Disrupted metabolism and insulin sensitivity

Diets high in ultra‑processed foods have been shown to increase insulin resistance, impairing the body’s ability to regulate blood sugar. ^[3] Almarshad MI, Algonaiman R, Alharbi HF; Relationship between ultra-processed food consumption and risk of diabetes mellitus: a mini-review. Nutrients. 2022;14(12):2366. Published June 7, 2022. doi:10.3390/nu14122366.

Increased fat storage and weight gain

These foods can lead to overeating and excessive calorie intake, often resulting in approximately 500 extra calories per day, which can contribute to weight gain and increased fat storage. ^[4] Hall KD, Ayuketah A, Brychta R; Ultra-processed diets cause excess calorie intake and weight gain: an inpatient randomized controlled trial of ad libitum food intake. Cell Metab. 2019;30(1):67-77.e3. doi:10.1016/j.cmet.2019.05.008. This is partly because these foods are not nutritious and therefore not very filling, yet tend to be high in calories.

Impaired gut health

Eating too many ultra‑processed foods can disrupt the balance and diversity of beneficial gut bacteria, which are vital for digestion and immune health. ^[5] Rondinella D, Raoul PC, Valeriani E; The detrimental impact of ultra-processed foods on the human gut microbiome and gut barrier. Nutrients. 2025;17(5):859. Published February 28, 2025. doi:10.3390/nu17050859.

Inflammation

A diet rich in ultra-processed foods is also linked to low-grade inflammation throughout the body, a known risk factor for chronic diseases. ^[6] Tristan Asensi M, Napoletano A, Sofi F; Low-grade inflammation and ultra-processed foods consumption: a review. Nutrients. 2023;15(6):1546. Published March 22, 2023. doi:10.3390/nu15061546

Mental health problems

A higher intake of ultra‑processed foods has been associated with an increased risk of depression and anxiety symptoms, particularly in those with lower physical activity. ^[7] Lane MM, Gamage E, Travica N; Ultra-processed food consumption and mental health: a systematic review and meta-analysis of observational studies. Nutrients. 2022;14(13):2568. Published June 21, 2022. doi:10.3390/nu14132568.

Nutrient deficiencies

These foods often lack key nutrients, such as fiber, vitamins, and minerals —nutrients essential for health and satiety (i.e., fullness from eating food). For example, a large study involving more than 2,000 people found that those who ate more ultra-processed foods had a lower intake of dietary fiber. ^[8] Schönenberger KA, Huwiler VV, Reber E; Dietary fibre intake and its association with ultraprocessed food consumption in the general population of Switzerland: analysis of a population-based, cross-sectional national nutrition survey. BMJ Nutr Prev Health. 2024;7(1):26-37. Published January 16, 2024. doi:10.1136/bmjnph-2023-000727.

Common Food Patterns and Ingredients to Watch Out For

To support your health, here are the top processed foods to avoid and ingredients to minimize:

Foods with refined grains

Refining removes the bran and germ from a whole grain food, stripping away fiber, vitamins, and minerals. ^[9] Dunford EK, Miles DR, Popkin B; Whole grain and refined grains: an examination of US household grocery store purchases. J Nutr. 2022;152(2):550-558. doi:10.1093/jn/nxab382. This leaves behind quick-digesting starch with less nutrition and a higher blood-sugar-spiking potential. Examples of refined grains include white bread, instant noodles, and crackers.

Snacks with hydrogenated oils/trans fats

Hydrogenation forms a more solid and shelf-stable oil, but it creates trans fats in the process that can be detrimental to health. ^[10] Pipoyan D, Stepanyan S, Stepanyan S; The effect of trans fatty acids on human health: regulation and consumption patterns. Foods. 2021;10(10):2452. Published October 14, 2021. doi:10.3390/foods10102452. Fortunately, these fats are no longer in many foods due to their health effects, but can still be found in commercial baked goods, such as donuts, cookies, and cakes.

Beverages with added sugars

Liquid sugars like soda, sugary coffees, and energy drinks bypass the natural satiety cues you’d get from whole foods, delivering a concentrated dose of added sugar without fiber or nutrients to slow absorption. [2] Out of all ultra-processed foods, sugar-sweetened beverages like this are most closely associated with inflammation in the body. ^[11] Ma X, Nan F, Liang H; Excessive intake of sugar: an accomplice of inflammation. Front Immunol. 2022;13:988481. Published August 31, 2022. doi:10.3389/fimmu.2022.988481.

Frozen meals with preservatives and flavor enhancers

Packaged frozen meals often rely on salt, nitrates, MSG, and additives to enhance taste and prolong shelf life, which can mask poor ingredient quality and reduce freshness. ^[12] Warner JO; Artificial food additives: hazardous to long-term health? Arch Dis Child. 2024;109(11):882-885. Published October 18, 2024. doi:10.1136/archdischild-2023-326565. Some frozen meals are healthier than others, particularly those that are lower in sodium, saturated fat, and preservatives that are more closely linked to metabolic issues.

Artificially flavored or colored snacks

Snacks such as potato chips, candy, and other baked goods often rely on chemical flavorings and dyes to enhance their taste, ingredients that many governing bodies consider an unnecessary risk to public health. ^[13] Amchova P, Siska F, Ruda-Kucerova J; Food safety and health concerns of synthetic food colors: an update. Toxics. 2024;12(7):466. Published June 27, 2024. doi:10.3390/toxics12070466. In addition, the base ingredients typically consist of refined starches, added sugars, and oils that contribute little to their nutritional value.

What to Look for on the Ingredient Label

To choose a better-for-you processed food, look for the following on the nutrition label.

• No “hydrogenated” oils: This ingredient indicates trans fat is present, where no amount of it is considered safe for consumption.
• Added sugars: Look for products with 7 grams of added sugar per serving or less when possible to stay within the daily limit of 24 grams for women and 36 grams for men. ^[14] Added Sugar. Harvard T.H. Chan. The Nutrition Source. Published August 5, 2013. Other names for added sugar on the label include dextrose, high-fructose corn syrup (HFCS), or sucrose.
• Sodium content: Try to steer clear of products that contain more than 20% of the Daily Value (DV) for sodium, as this can help protect your heart, blood pressure, and overall health.
• Emulsifiers and chemical thickeners: Limit your consumption of products containing ingredients like carageenan and polysorbate 80, which are thickeners that may increase the risk of metabolic disorders, cognitive decline, and gut inflammation when consumed in excess. ^[15] Liu F, Hou P, Zhang H; Food-grade carrageenans and their implications in health and disease. Compr Rev Food Sci Food Saf. 2021;20(4):3918-3936. doi:10.1111/1541-4337.12790. , ^[16] Zhang L, Yin Z, Liu X,; Dietary emulsifier polysorbate 80 exposure accelerates age-related cognitive decline. Brain Behav Immun. 2024;119:171-187. doi:10.1016/j.bbi.2024.03.052.

How to Eat Less Processed Food

Cutting down on processed food doesn’t have to be hard. Here are a few simple ways to start moving in the right direction.

• Cook more at home: Use whole, raw ingredients found on the perimeter of the grocery store whenever possible. Meal prepping ahead of time on weekends makes it easier to include these foods on busy weekdays.
• Choose “single-ingredient” or minimal ingredient packaged foods, such as steel-cut oats instead of instant oatmeal.
• Replace processed snacks with fresh alternatives, such as fresh fruit, vegetables, nuts, pumpkin seeds, or plain yogurt. Not only are these foods better for you, but they are also more filling.
• Start slow: Replace one ultra-processed item per week with a minimally processed or whole food version.
• Be realistic: It’s about progress, not perfection, so give yourself grace as you make the transition to a less processed diet.

Conclusion

Processed foods aren’t inherently harmful; the key is understanding the ingredients in the food you’re eating and using this knowledge to guide mindful choices. By focusing on whole and minimally processed foods while reducing your intake of ultra-processed items high in sugar, saturated fat, and sodium, you can enhance your nutrition, support better health, and lower your risk of chronic disease.

Even small, steady shifts—like swapping one packaged snack for a whole food option—can make a meaningful difference over time. If you don’t know where to start, consult a registered dietitian, who can provide individualized guidance in your journey to better health.