What is in Processed Foods?

Americans have a long history of creating boogeymen out of food. Sometimes it’s justified, sometimes not so much. There was the outrageous cigarette diet of the 1920’s. Then there was the very unsatisfying grapefruit diet of the 30’s. This was followed by the rejection of all fats, carbs, and innocent gluten in the 2010’s, and most recently, processed foods. Many of these recent fads don’t have enough basis in actual science. They ignore the fact that there are good fats, like avocados. They also ignore that there are good carbs, like whole grains, and that unless you have celiac disease or an allergy, there is nothing inherently unhealthy about gluten. Processed foods are a mixed bag too. New diets like Whole 30 and Paleo condemn processed foods entirely, but why? What is in processed foods that supposedly makes them unhealthy? 

First off, let’s nail down what defines processed food. Food that’s been processed has been nutritionally altered in some way, whether through cooking, canning, freezing, packaging or other processes. This is done for a number of reasons, whether it’s to preserve the food and give it a longer shelf life, or to make it taste better. Technically, every time we cook up a meal, we’re processing the food we use. Some typical processed foods are potato chips, cereal, milk (because it has been pasteurized), and bread. None of these foods are raw products. Bread wasn’t picked from a bread tree, it was manufactured. There are different levels of processed food, and not all of them are bad for you. 

Types of Processed Food

Minimally processed foods are usually whole foods that have been slightly altered for easier use. Things like bagged fresh lettuce, chopped fresh vegetables in packages, roasted almonds, or vacuum sealed packages of raw meat are all minimally processed foods. Processes like cleaning, cutting, or vacuum-packing are all types of processing, but they don’t significantly change the nutritional content of the food. 

The next level up are products made with minimally processed ingredients. For instance, pasta that is made with whole grains would be in this category. The grains are a raw food ingredient that was processed into pasta. Whole grains are a very healthy, wholesome ingredient that creates a healthy, yet processed, food product. Other examples are olive oils, peanut oil, or sesame oil. These are products made from natural, whole ingredients through some form of processing. 

Fast food on a yellow background
Nazarov, Sergey. Getty Images. 2020. jpeg file.

Processed foods are foods from either of the last two groups mentioned, with extra ingredients added for taste like sugar, salt, or fats. They usually have two or three ingredients, and you can eat them right away without any added preparation. Examples of this kind of processed food are some kinds of canned fruits, veggies, and fish, as well as fresh-made bread and some kinds of cheese. It can also mean foods like bacon and granola bars.


Ultra Processed Food

Ultra-processed foods should definitely be avoided, and are often what people mean when they say “processed foods”. These foods not only have salt, sugar, and fats, they can also have artificial colors, flavors, and preservatives to make them look more appealing and last far longer. Examples of this are lunch meats like bologna, instant mashed potatoes, and frozen pizzas. There is even evidence to suggest that ultra-processed foods have addictive qualities.

In a study by the University of Michigan’s Department of Psychology, participants were asked to report on their loss of control over their eating habits while they consumed 30 foods with different levels of nutrition. The participants then answered questions about the effect foods had on them in terms of liking, pleasure, craving, and intensity. These were to measure the likelihood that the participant would abuse or overeat that food. The results showed that highly processed foods that had added fats, refined carbohydrates, or both, tended to cause more loss of control, more pleasure, and more craving.


Ultra Processed Foods including a burger, a Dorito, Hot Cheetos and Babybel cheese 

Ultra-processed foods also tend to be the easiest to prepare. Things like frozen dinners, breakfast cereals, and lunch meats are quick and easy, which increases their appeal even more. They are also often low in nutrients and fiber, so they have less nutritional value. A study from the University of Sao Paulo found that 60% of calories consumed by Americans are from ultra-processed foods. The same university conducted another study that suggests a connection between the surge of ultra-processed food sales and the increase in obesity.

Now that we know about the levels of food processing, what are some of the different ways that food is processed, and what exactly do they do to the food? Knowing this will help you know what processed foods are perfectly healthy, and which ones should be banished from your shopping cart.


Canned vegetables on Kitchen table opened tin cans on kitchen table.

To can food, it’s heated up to a very high temperature in order to kill any harmful bacteria. It’s then put into an air-tight can and sealed. This seals in the food when it’s at its freshest and most nutritious, which can’t be said for fresh food at the grocery store. The moment produce is picked, it begins to lose its nutrition, and the time it takes to get to the grocery store, into your shopping cart, and onto your plate can take a while. Canned fruits and vegetables don’t have this problem, as their nutrition is preserved by the canning process.

The University of Illinois even conducted a study that found that canned produce can have just as much dietary fiber and vitamins as fresh produce. It even found that in some cases, it can actually have more. One example of this is pumpkin. Canned pumpkin contains 540% of the recommended daily dose of vitamin A, but fresh pumpkin only has 26%. Also, Canned pumpkin has about a fifth of the iron you need in a day. Canned produce also tends to be more affordable. Not everyone can afford to eat fresh fruits and vegetables every day, and certain canned produce can create more accessibility to healthy food. Just check the ingredient list for artificial additives! 


Additives are exactly what they sound like: a substance that is added to a food for a number of reasons. This form of food processing can be the trickiest to navigate, since there are so many different kinds of food additives out there. Additives can be used in processed foods to preserve freshness, flavor, appearance, or texture. They can be anything from natural spices like cinnamon to artificial flavor enhancers. These are chemicals that amplify the food’s already existing flavors without adding a new flavor. 
Ingredients in whole, minimally, and ultra processed food infographic

Ho, Lucy. 2021. jpeg file.

There are many different types of additives, some natural, some not. Some additives are bad, such as the preservatives used in processed meats, called nitrates, which have been proven to increase the risk of colon cancer. Others, like whey protein, are used to create a creamy texture without the use of fat. Whey protein is a natural additive that is a primary protein found in dairy. Unless you’re lactose intolerant, this is a safe additive. There are a wide variety of additives, and a good general rule is that if you find an ingredient hard to pronounce, look into it before buying a product that contains it. The FDA has a graph that is a handy resource.



If you’re going to eat frozen foods, get frozen whole foods like produce or raw meat, rather than frozen pre-made meals, which are ultra-processed. Freezing is one of the more trustworthy processing methods of preserving whole foods since usually nothing is actually added to the food. Still, be sure to check those labels!

Frozen vegetables on a tableDuring the freezing process, fresh vegetables can lose some color, flavor, or nutrients. This is because of enzymes, a chemical compound in fruits and veggies, that break them down over time. To stop enzymes from doing this in vegetables, they are often blanched before being frozen. This means that the veggies are briefly boiled or steamed, then quickly cooled down in ice water to stop the cooking process. This process deactivates the enzymes, keeping the veggies from breaking down, and also saves you a step in the cooking process.

Enzymes in fruit are a different story- they cause fruit to brown and lose vitamins. Since fruit is usually eaten raw, blanching isn’t a good option to stop this. Instead, ascorbic acid is usually used, also known as vitamin C. Vitamin C is not only good for you (it’s essential for healthy body tissue), it also controls the deterioration of fruit. Ascorbic acid in its purest form is what you want. It’s sometimes mixed with unhealthy ingredients, like sugars. Or, if you don’t mind a little bit of browning on your fruit, none at all! 


This process is most commonly used with milk, and sounds a lot more complicated than it is. Pasteurization is when food is heated to a high temperature and then rapidly cooled down, which kills harmful microorganisms like mold and yeast. This prevents you from getting any possible food borne diseases, and makes the food safe to eat. In addition to milk, this is also used in juice and canned foods.
A girl in a red plaid shirt holds out a glass of milk


Variety of fermented vegetables, kimchi in glas jars, marinated canned food, natural probiotics, healthy eating, prebiotic rich food for digestion and healthy gut, immunity boost, food processingFermentation is used to make yogurt, kombucha, pickles, cheese, sourdough bread, and alcoholic drinks like beer and wine. During fermentation, microorganisms like yeast and bacteria convert carbohydrates like starch and sugar into either alcohols or acids. These acids stop  bad bacteria from growing. This not only gives the food a tart, acidic flavor, it also preserves the food naturally. Fermentation is a form of food processing that actually has a lot of health benefits. For instance, it creates good bacteria known as probiotics, which help with digestion. Studies have shown that they help with the immune system as well. Fermentation also helps make the food easier to digest, since it  breaks down nutrients that your body would have had to break down instead.

Interestingly, fermentation can also make some dairy products, like yogurt and kefir, safe for those who are lactose intolerant. It does this by breaking down the lactose in the dairy product and turning it into compounds like glucose and galactose, which are easier to digest.  

There are even some studies that suggest that fermented foods are good for mental health! Certain kinds of probiotics found in fermented foods have been linked to reductions in anxiety and depression. This is part of a growing amount of scientific evidence that links gut health to mental health.


Meat smoking in a smoke house

This is a chemical process that involves heat from smoke being used to treat food in a way that makes it last longer.  Usually done by burning wood, this process is used for meat, sausage, fish, and cheese, and can also be used for drying fruit. The most well known example of the smoking process is smoked salmon, or lox.

Smoking preserves food by removing moisture from it. Moisture can cause the growth of bacteria or fungus, so taking it out of the equation increases the shelf life of the food. It also adds that distinct, delicious smoky flavor. However, sometimes sulphur dioxide is used in dried fruit. Sulphur dioxide is a preservative and is alright for healthy people to consume in limited amounts, but it can cause asthma attacks. It’s best to avoid it altogether.


When it comes to processed food, there is good and bad. Minimally processed, and even mid-level processed food can be healthy, more affordable, easy to prepare, and even have great health benefits. Ultra processed food is the true boogeyman, and almost always contains harmful ingredients. Stick to minimally processed foods that contain whole ingredients, and if you’re not sure, do some research before buying. There are plenty of healthy foods that have been processed. In order to identify them you should:

  • Know the different types of processing 
  • How they’re used
  • Stick to whole or minimally processed foods
  • Watch that ingredient list! 

Learn more about what’s in your food in our Health Benefits section!

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Olivia deGregory

Written by Ariana Lipsman