Highly Processed Food

Last updated: November 22, 2022

Daniel Mališ
Daniel Mališ

Most people know that highly processed food is unhealthy. But some food processing is often necessary, so where do we draw the line? Is there even such a line? And why is highly processed food so unhealthy?

In the Introduction to Unhealthy Food, we’ve already learned the principle that unhealthy food is any food that is not natural. I also explained the reason – the human body had almost no evolutionary time to adapt to unnatural substances, nor is it well designed to adapt to them in general.

Food can be unnatural in many ways, but the result is always the same. Our bodies’ attempts to tackle something they’re not designed for end up in chronic inflammation, the common denominator of most chronic diseases.

Plus, as an added “bonus,” unnatural food has many other negative effects.

Highly processed food (sometimes called “ultra-processed food”) is a classic example of unnatural food. So let’s dive in.

Understanding the Continuum

What exactly is “highly processed” food? To understand the term, the Eleventh RCM Attitude – perceiving things on a spectrum – comes in handy again. Why?

Because there’s a whole continuum of foods, starting from completely unprocessed food like an apple you just plucked from a tree and ending with food such as imitation “sausages” that contain almost no meat, but a lot of weird stuff instead.

It’s not just no processing vs. ultra-processing, as shown in the picture. There’s also some healthy food processing in between.

Eating food in its purely natural form, i.e. unprocessed food, has many health benefits but it’s often not practical, since it severely limits your food choices. No one really eats raw meat (with rare exceptions like steak tartare). And even raw vegans allow for certain preparation methods for the vegetables they eat, such as juicing, blending, and dehydrating.

Besides that, eating only raw food is rather extreme, and as such, this dietary approach can only be beneficial in the short- or mid-term, not in the long run.

This applies to many other diets, by the way. As a general rule, various extremes are good as a tool, but not as a permanent state. Think of physical exercise, saunas, cold plunges, etc. Would you do it all the time?

But back to highly processed food.

There are three main types of food processing:

  • Physical – processing food using either mechanical force, high/low temperatures, or increased pressure
  • Chemical – putting in various food additives, or bringing about chemical processes such as fat hydrogenation
  • Biological – subjecting food to microorganisms, such as bacteria or yeasts for fermentation

We’ll go over each type of food processing below, which will help us understand the principles.

Physical Food Processing

There’s absolutely nothing wrong with basic physical food processing, such as cutting, removing inedible parts, grinding, drying, refrigeration or freezing, heating, boiling or cooking.

In principle, you’re using some form of energy to make the food edible or more digestible – either mechanical energy (cutting, removing inedible parts, grinding) or thermal energy, which you either add to (drying, heating, boiling, cooking) or remove from the food (refrigeration, freezing).

Pressure cooking essentially uses both thermal and mechanical energy, as you’re constraining the expanding air within the same container volume.

However, manufacturers of highly processed food go beyond those basics – they also remove the “unwanted” parts, calling it “refining” the food. This is mostly a physical process, although it usually involves some chemical processing as well.

As usual with most nice-sounding descriptions used for marketing purposes, also “refining” covers up something quite detrimental – in this case, a process that strips the food of important nutrients and fiber, leaving only bare macronutrients such as starch and proteins (glutens).

Why are the food manufacturers doing it? It has nothing to do with your health and everything to do with a convenient and more profitable sales process.

For example, traditional milling of grains removes neither the outer layers of grain (bran), nor the part from which the grain sprouts in nature (the germ). Bran is an excellent source of dietary fiber and B vitamins. The germ is even richer in important nutrients, such as B vitamins, carotenes, and omega-3 fatty acids.

Bran, germ and endosperm – three main parts of a grain. The first two contain most of the grain’s micronutrients. The inner part (endosperm) is mostly empty calories and gluten, except for its outermost aleurone layer, which however remains attached to the inner layer of the bran during milling.

However, the fats contained in the bran and germ make the flour look a bit yellowish, and become rancid over time, shortening the flour’s shelf life. So food manufacturers found a simple solution – let’s remove the “naughty” parts!

The problem is, however, that by removing the bran and germ, they are also removing the associated vital nutrients, leaving only the empty calories contained in the rest of the grain (called the endosperm). This ends up with calorie-rich but fiber- and nutrient-poor “refined” flour.

Once consumed, the starch in the refined flour quickly breaks down into glucose, spiking the blood glucose levels and priming the body for insulin resistance, which is the biological mechanism behind Type 2 diabetes.

The process leading to “refined sugars” is even more extreme – literally everything is removed from the original plant (sugar beet, sugar cane, corn, etc.) during slicing, soaking, squeezing, melting, crystallizing and other processes leading to “pure” saccharides such as glucose, fructose or sucrose (aka table sugar).

Sucrose, better known as table sugar, is a disaccharide composed of glucose and fructose.

Compare that to eating fruit – you also consume sugars like glucose and fructose, but the fiber in the fruit slows down the digestion and absorption of these sugars, which means they get into the bloodstream more steadily, as opposed to their sudden spike. Plus, you get a lot of beneficial micronutrients, such as vitamins, minerals and phytochemicals contained in that fruit.

Dietary fiber is very important. Apart from mitigating the quick release of sugar into your blood, it serves two more important functions. First, fiber helps you feel satiated, which prevents overeating. Second, fiber feeds beneficial gut bacteria in your gut – yes, the bacteria also need to eat something, and fiber is their preferred food.

Highly processed food removes all the above benefits of natural food, and only provides you with empty calories that lead to overeating, obesity and chronic illnesses.

Chemical Food Processing – Food Additives

As outlined above, chemical food processing involves putting in various food additives, or bringing about chemical processes such as fat hydrogenation. Let’s start with food additives.

There are two basic types of food additives – natural and artificial. The natural ones typically include salt, sugar, vinegar, and natural fats. If used in moderation, they don’t present any health risks.

But as you know, food manufacturers don’t like moderation, in particular when it comes to salt and sugar.

Now artificial additives, another favorite of food manufacturers. The list of artificial food additives is almost endless, but here are some examples of the most common categories:

  • Preservatives (such as sodium benzoate or sodium nitrate)
  • Flavorings and flavor enhancers (like the notorious monosodium glutamate)
  • Sugar substitutes (artificial sweeteners such as aspartame or cyclamate)
  • Colorings (artificial dyes and pigments)
  • Emulsifiers (preventing oil-water mixtures from separating)
  • Glazing agents (giving foods a shiny appearance)
  • Antifoaming agents (antifoams and defoamers)
  • Humectants (preventing foods from drying out)

With most of the categories listed above, I’m not even giving examples of the actual substances, as I don’t want this article to turn into a chemistry class. But you can have a look at the picture below.

Meet some of the food additives present in ultra-processed food – monosodium glutamate (E621), sodium benzoate (E211), sodium propionate (E281), aspartame (E951) and butylated hydroxytoluen (E321). Bon appetit!

Again, regardless of the artificial food additive, the issue is always the same – our bodies are not designed to deal with such substances, which results in chronic inflammation and all the diseases and disorders associated with it.

However, the list of negative health effects of artificial food additives doesn’t end with chronic inflammation.

Let’s take artificial preservatives, one of the most frequent food additives, as an example. They don’t only extend the shelf life of the food, but also kill the bacteria and other beneficial microorganisms in your gut.

Think about it. The preservatives such as sodium benzoate are added to the food exactly with the intent to kill the bacteria that would make the food go bad faster. Will the preservatives all of a sudden stop killing other bacteria when they end up in your gut? They won’t.

As a result, your gut microbiome, the closest ally of your all-important immune system, takes a hit every time you ingest a food product that contains artificial preservatives to extend its shelf life.

Another significant problem with artificial preservatives is that they often turn into metabolites that cause cancer. Cancer is also linked to chronic inflammation that we already talked about, but it’s worth making this point separately.

For example, sodium benzoate (the artificial preservative I mentioned above) converts to benzene, which is a known carcinogen. Sodium nitrate, a common preservative used in processed meat (because it also gives the meat a nice reddish-pink color), can turn into nitrosamines, which are also carcinogenic. No wonder the incidence of cancers is constantly on the rise.

The meat products you see wouldn’t have such a nice reddish-pink color (and wouldn’t last for so long) without sodium nitrate, a precursor to carcinogenic nitrosamines.

I won’t go over each category of the food additives listed above; you already got the idea. But I will briefly mention one more category here – colorings, in other words artificial dyes and pigments.

Again, they cause chronic inflammation like all other artificial substances, but they are also particularly dangerous for the developing brains of children, which is associated with their behavioral problems such as aggression, attention deficit disorder (ADD) and attention-deficit/hyperactivity disorder (ADHD).

The nice colors certainly catch children’s attention, but the artificial dyes and pigments behind the colors are later responsible for attention-deficit and other behavioral disorders in children.

Next time you think about buying something like this for your child, think twice. The colors look nice, but are they worth the health risks?

If you have time, I recommend watching this 18-minute TEDx Talk on the effects of artificial food dyes on child development.

Chemical Food Processing – Fat Hydrogenation Etc.

Apart from putting in various food additives, the other type of chemical food processing is inducing chemical processes in food. Let’s see the big picture first.

In living organisms, which of course include the plants and animals that we later eat, molecules react by intelligently communicating with each other. In these cases, chemical reactions occur under standard (naturally occurring) temperatures and pressures, facilitated by enzymes and other naturally occurring catalysts.

(Catalysts are substances that are not consumed in chemical reactions, but make them easier.)

In synthetic chemistry, there’s less intelligence around the way molecules communicate with each other. As a consequence, chemical reactions typically have to be pushed by very high temperatures and pressures, often with the help of heavy metals as catalysts.

Not surprisingly, the end products of such reactions differ from their counterparts achieved by natural synthesis, or they don’t exist in nature at all.

Inducing chemical processes (reactions) in food stands between the above two poles. The plants and animals used for food are no longer alive, but are still products of nature. Due to prevailing agricultural methods, the food unfortunately often contains artificial chemicals like glyphosate, but it’s not all synthetic.

However, that doesn’t prevent food manufacturers from using methods of synthetic chemistry when processing food. One such method is fat hydrogenation.

Fat hydrogenation is a process when you take liquid vegetable oils (which are themselves highly processed), subject them to high temperature and pressure, add a heavy metal (usually nickel) and introduce hydrogen gas.

If you fancy some chemical details, the applied high temperature and pressure cause some of the double bonds between chained carbon atoms in unsaturated fats to break, which results in the creation of single carbon bonds, with the “leftover” bonding capacity of carbon used to bind the added hydrogen. The unsaturated fats (liquid oils) thus become partly saturated with hydrogen, which makes them semi-solid or solid, depending on the degree of hydrogenation.

This consistency makes hydrogenated fats more “manageable” – they don’t leak like oils, are easily spreadable (think of modern margarine), don’t have to be refrigerated like butter, and are generally more stable, which extends the shelf-life of the products that contain them.

These are all ideal qualities for food manufacturers, but there’s a big catch for the consumers.

In carbon chains of natural unsaturated fats, hydrogen atoms bind on the same side of the double bonds between carbon atoms – this is called a “cis configuration.” However, under the unnatural process of fat hydrogenation, most of the hydrogen atoms end up on different sides of the remaining double bonds, reaching the “trans configuration.” That’s why hydrogenated fats are also called trans fats.

The difference between cis-fat and trans-fat molecules. Notice the varying location of the red hydrogen atom attached to the double-bonded (C=C) carbon atoms.

While this may sound like an unimportant chemical subtlety, the trans configuration in fats has a hugely negative effect on human health. As with almost anything unnatural that gets into the human body, also trans fats lead to chronic inflammation and have been linked to many diseases, from cardiovascular disease to diabetes and cancer.

Consequently, health authorities such as WHO and FDA warn against trans-fats and want to eliminate them from the food supply.

Despite that, trans fats are still used by food manufacturers, although in limited amounts, so any time you eat highly processed food, you’re likely consuming the harmful trans fats.

Margarine, which is basically semi-synthetic fat, is still sold around the world. In the US, the manufacturers are even allowed to claim there are no trans fats if the product contains less than half a gram of trans fat per serving. So you can have 0.49 grams of trans fats in each serving of “zero trans-fat” margarine.

A quick historical note (as we should always learn from history): I remember that in the early 1990s, when I was studying medicine, trans fats like margarine from vegetable oils were heavily promoted as a “healthy” alternative to “dangerous” animal fats.

Leading cardiologists repeatedly explained how consuming hydrogenated instead of animal fats leads to lower cholesterol levels and quoted numerous scientific studies to support the claim that trans fats are beneficial for human health.

Various medical associations issued recommendations in support of hydrogenated fats, and health authorities were of course of the same opinion. Anyone who was questioning the safety of hydrogenated fats was either ridiculed or accused of ignoring the science.

After so many people needlessly suffered from chronic diseases and died prematurely, doctors, scientists, medical associations and health authorities are now saying the exact opposite of what they were actively promoting up until 1990s, without acknowledging this complete about-face.

Not surprisingly, the Wikipedia page on trans fats makes no mention of the infamous history of misguided recommendations. And good luck trying to change that – your Wikipedia contribution won’t stay for long.

Lessons learned? Favor natural over synthetic, think critically, question authorities and learn from history. The scenery and cast may change, but the plots and characters repeat over and over. Keeping to time-tested principles is the best approach and defense.

Now back to food processing again.

Biological Food Processing

Biological processing primarily involves subjecting food to microorganisms for fermentation, typically using bacteria or yeasts. If timed and controlled well, fermentation yields very healthy food such as kimchi, sauerkraut (bacterial ferments) and kombucha (bacterial and yeast ferment).

Kombucha is a fermented drink that you can make easily at home. You just need a fermentation starter abbreviated as SCOBY, which stands for “symbiotic culture of bacteria and yeast.” The picture shows a grown-up SCOBY in the kombucha brewing jar, just below the liquid surface.

Yeasts typically cause ethanol (alcoholic) fermentation, so their solitary ferments are less healthy, although in moderate amounts, there are some health benefits too. I’m sure you can come up with examples – indeed, beer and wine are the most frequent alcoholic ferments.

Apart from bacteria and yeasts, also some “noble” molds, such as Penicillium roqueforti and Penicillium camemberti, are used for fermentation. As you can guess from the name, the end products are various types of blue cheese, such as Roquefort, Camembert and Brie. Molds are neither bacteria nor yeasts, but fungi.

A quick side note: We think of fermentation as a way of naturally preserving food, making it a source of probiotics and unlocking its flavor, or in terms of the end products such as beer and wine. But for microorganisms, fermentation is mainly a way of extracting energy from carbohydrates without the need of oxygen. We all eat to get energy in the first place.

Because of its natural character, biological food processing doesn’t lead to highly processed food. But that doesn’t mean that some mass-produced fermented products haven’t been through a fair amount of processing.

This applies for example to blue cheeses (which are subject to pasteurization, acidification, coagulation, salting and sterilization) and non-organic wines, which contain additives like sulfites and ammonium phosphate, not to mention the use of GMO yeasts.


Hopefully, the above framework gives you enough understanding of what highly processed food is a why you should avoid it. If you eat it occasionally, it’s no big deal, but regular consumption of ultra-processed food is a significant health risk.

If in doubt, you should avoid regular consumption of the following foods, as they’re likely to be ultra-processed:

  • Anything with five or more ingredients (i.e. most pre-packaged foods, which are loaded with various artificial additives)
  • Anything that is “refined” (e.g. white bread and any baked goods made with white flour)
  • Margarine and anything with the word “hydrogenated” in its list of ingredients
  • Anything with ingredients that you can’t pronounce (unless you’re a chemistry major)
  • Anything containing high-fructose corn syrup or artificial sweeteners (that also includes carbonated soft drinks)
  • Sweet, fatty or salty packaged snacks
  • Packaged “instant” meals, including instant soups
  • Chicken nuggets, fish fingers, burgers, hot dogs and sausages
  • Anything with a shelf-life longer than a year (how many healthy foods do you know that last that long?)
  • Anything that is promoted on TV – they never run commercials for healthy food.

Often promoted in TV commercials, most cereals are also highly processed – full of refined grains, preservatives, artificial dyes and added sugar.

Instead, you should adopt a nutritional lifestyle based on whole foods, such as vegetables, fruits, legumes (lentils, chickpeas, and beans), herbs, rice (brown if possible), and, in moderation, fish, poultry, meat and eggs, all preferably from organic or naturally raised and fed sources. Your body will thank you!


And now, it’s your turn! Which part of the article did you find the most surprising? Which ultra-processed food do you have problems dropping from your diet? Or is there anything else you’d like to share with us?

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