Chemical food processing. What is it? Why is it dangerous?

Earlier In Defense of Processed Food, I critiqued Metabolical. In it Robert Lustig rejects all processed foods. Also, I described specific food processes deemed acceptable by NOVA. Some critics divide food processes into mechanical and chemical. Mechanical processing claims to be benign. It should not form dangerous chemicals, strip out stuff, or change food properties.

Chemical food processing adds chemicals to foods. These chemicals are refined ingredients and artificial substances. Such additives have little or no nutritional value. It differs from mechanical processing—most of which appear in NOVA Groups 1-3. Chemical processing results in ultra-processed foods. Known as ‘industrial formulations’ they consist of ingredients added in precise amounts. Processors add these ingredients at specific points of the process. It is the commercial counterpart of a recipe. Michael Pollan introduced

          Rule #6—Avoid foods that contain more than five ingredients.

NOVA adopted the 5-ingredient rule into its initial classification system. After criticism for over-simplification, it dropped the rule. Few if any foods dropped out of Group 4 in future versions. Note there are no limits on the number of ingredients for home recipes.

The idea that mechanical processing fails to affect the chemistry of foods is wrong. Almost all acts of food preparation strip out stuff or change food properties. Many types of food preparation can form dangerous chemicals. As we bake bread, brown pigments form on the surface of the heated dough. Those pigments result from a series of chemical reactions known as Maillard browning. Molecules leaving the surface of a roasting chicken find their way up our noses. These odors are combinations of desirable chemicals. Jams and jellies use complex networks of carbohydrates to achieve the proper structure. Shirley Corriher illustrates chemical changes in the kitchen in KitchenWise.

Ultra-processing is not about processing. It is about ingredients. Robert Lustig’s tells us in Metabolical is that processing adds preservatives. NOVA’s main criticism goes beyond Lustig. Ultra-processed foods include food additives. NOVA assumes that all food additives not designated as culinary ingredients are harmful. It lists 23 unacceptable types of ingredients and 9 forbidden types of foods. These ingredients and foods are not recent additions to our diet, many have been around a long time. Sausages, one of the forbidden foods, date back to 500BCE. Ice cream, another forbidden food, dates back almost as long. Commercialization of ice cream started in Baltimore in 1851. ‘Meals’ appears as a third forbidden food. It is permissible to fix meatloaf or chicken fettucine at home but not in a processing plant.

Clean Trix
Clean label for Trix cereal. Is this product ultra-processed?

Each ingredient in an industrial formulation or in a home recipe has a function. Big Food scrambled to hide functional ingredients in its products behind clean labels. Instead of using a forbidden emulsifier, product developers use egg yolk solids. Lecithin is the natural chemical in egg yolks that emulsifies foods. Egg yolk solids are more expensive than lecithin or other emulsifier. They also come with other properties that may lower the quality of the product. Soy sauce substitutes for MSG. Celery salt cures meat without the connotation of natural nitrates. Cranberry juice delivers the power of benzoic acid without naming the functional chemical.

NOVA grandfathers in processed culinary ingredients. It encourages us to avoid ingredients not used in typical culinary preparations. Many of these additives are now available to home cooks on Amazon. Jeff Bezos founded the company July 1, 1994. Are we now limiting culinary innovation in the kitchen to before 1994?

Preservatives and other additives are the real targets of NOVA. Preservatives are substances added to foods to prevent decay. Decay is spoilage due to growth of microbes. Food scientists also include substances added to prevent other types of food spoilage. Antioxidants limit oxidation of fats. Emulsifiers keep oils from separating out of a product. Humectants keep moist foods from drying out. Presence of an emulsifier or a humectant categorizes a food as ultra-processed. Presence of antioxidants or antimicrobials do not. The two preservatives most often found in foods are sugar and salt. They bind water making it more difficult for microbes to grow. Preservatives decrease food waste. Which is worse—consuming foods containing preservatives or promoting food waste?

Food additives are ingredients in products that affect their characteristics. These additives have a specific function analogous to ingredients in a recipe. Additives affect color, flavor, texture, stability, and nutrition of a processed food. Many of these additives convert a processed food to an ultra-processed one. The main objection to food additives is that they enhance the flavor and color of products. Thus, additives give an ultra-processed food an unfair advantage over a natural one. Do sauces and glazes prepared by chefs and cooks do the same thing for culinary art? Note that additives include vitamins and minerals that enhance the nutrition profile. Added nutrients are not mentioned by NOVA.

The sneakiest thing about NOVA is what it doesn’t say about additives. Aided by its forerunner, Food Rules by Michael Pollan, NOVA rules hint at the danger of chemicals. Many food additives are chemicals appearing on the label with unpronounceable chemical names. Some chemical additives have common names that are not as scary like caffeine, salt, and sugar. Would we rather eat trimethylpurine dione, sodium chloride, or hex-2-ulofuranosyl hexopyranoside? They are the technical names for the same chemicals.

Rule #7—Avoid food products containing ingredients that a third-grader cannot pronounce.

Are all preservatives and other additives dangerous? Governmental scientists around the world do not think so. There are differences in regulation by country. There is more agreement between governments than disagreement. What gives public health professionals a right to condemn such a wide range of food products? I do not disagree that consumption of some of these foods can lead to health problems. Overconsumption of many of these foods is of more concern. How are a these scientists able to use an arbitrary standard to declare a large group of foods unhealthy? Where is the biochemical mechanism that links these foods to chronic disease? Why aren’t the vast selection of products divided into subgroups for further analysis?

A ray of hope! A recent correlation study subdivided ultra-processed foods into subgroups. It is still a correlation study that does not show causation, but it is a start. The study found that ultra-processed food increased risk of IBD. Soft drinks, sweet and salty snacks, and cured meat led to higher correlations (1). Dairy foods and starches did not. Scientists have proposed a biochemical mechanism for a connection of fructose to metabolic diseases. It is not yet accepted, but it provides a path to further study. I know of no other mechanisms linking ultra-processed foods to chronic disease.

Bottom line. Chemical food processing does not exist. It is another term opponents of food additives use to discredit them. Almost all food processes change the chemistry of a food. It is time to focus on the actual components of food not scare tactics that fail to help us understand. If we want a healthy food supply, let’s study the problem rather than using confusing terms.


(1) Narula, N. and 34 others. 2021. Association of ultra-processed food intake  with risk of inflammatory bowel disease: prospective cohort study. British Medical Journal 2021:374n1554 1.

Next week: Is it dangerous to eat microbe-modified foods?

8 thoughts on “Chemical food processing. What is it? Why is it dangerous?

  1. I’m adding a clarification and an observation.

    A formulation is the commercial counterpart of recipe. Okay, technically I guess your point is well taken. But folks who cook on a regular don’t usually follow recipes unless they are baking. Most good cooks adapt the dishes they make to the ingredients on hand and most cooks salt to taste as opposed to measurement. A formulation happens when a recipe is standardized for distribution. When I run the numbers on a recipe, I use gram equivalents for the ingredients and changing the amount or kind of ingredient changes the nutrition analysis. Industrial formulations are formulations mass produced on a massive scale. Home made lasagna will often not taste exactly the same each time. Not so with an industrially produced frozen lasagna.

    And my observation on chemical food processing. I’ve recently been doing some research into seed oils. I’ve discovered that the most common oils – canola, palm, corn, and soybean oil – are chemically extracted then refined, bleached, and deodorized. Hence RBD seed oils. A gentler extraction method is expeller pressed in place of chemical extraction. But the resulting oils are the refined, blanched, and deodorized. Extra virgin cold pressed olive oil on the hand retains more nutritive properties because no heat is applied. Framing these differences in terms of degree of processing, pressing oil out of olives may be an industrial process but using cold pressing requires neither a chemical solvent or the application of heat and, according at least to my olive oil provider, no further refining, bleaching, deodorizing is used with extra virgin.


    1. Points well taken. Since I took over as the primary cook in my home, I rarely follow a recipe. I use them for ideas on what spices to add to the main ingredients. Having said that, if I was a processor, I would need to follow the formulation as the ingredients must be listed on the pre-printed label in order of amount from highest to lowest, and the Nutrition Facts would also need to be accurate. No ingredient substitutions are allowed.
      With respect to oils, you are correct that extra virgin olive oil undergoes a less harsh process than other oils. I purchase Bertolli Extra Virgin Olive Oil off the grocery store shelf. I assume that it is as good as the one you use, and I have faith in the governmental regulatory process. Is it a RBD seed oil? I don’t know and don’t care. It serves my needs as a cook. I like the abundance of monounsaturated fatty acids and the lower level of fat oxidation. Many home cooks can’t afford EVOO and use canola, palm, corn or soybean oil. Regardless of what oil is used in a formulated food, if it contains a forbidden additive, it is an ultra-processed food according to NOVA.


  2. More debunking of the chemophobes, for which I thank you. I wish your words would go”viral,” especially your concern with overconsumption, but there would still be too much public discomfort in the conclusions. Two things I add and you may expect:

    1. Understand WHY the chemophobes’ conclusions are so popular and welcome — misunderstanding of corporations and competition, and fear of science which must deny the miracles and magic that feed and comfort us as we start our lives, and still need.
    As for third-graders, my 1st-grader grandkid told me that a plant I know as hen-&-chicks is really a sempervivum. He has one at home and parents told him the botanical name, pronounced OK although he may not know how to spell it yet.

    2. Importance of numbers and probability, rather than assuming that having something “in it” is all we need to know. This is OK with religious prohibitions, as they are not quantitative, but not OK for health, where quantity and probability certainly matter. We need look no further than the vax-antivax conflict to see this in the real world.
    HMM= How Much Matters.


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