A Processed Mindset

Does 'Ultra-Processed' Mean 'Unhealthy'?

“Processed foods” is a term that may bring to mind ready-meals served in plastic trays, ready to be nuked in the microwave for a few minutes, or junk food snacks laden with unpronounceable additives comprising an ingredient list the length of a short novel. However, whilst some modern processed foods are certainly unfavourable, many of us have an overly maligned viewpoint of the term. This automatic negative mindset is unwarranted: our food has been subjected to some degree of processing for thousands of years. Members of our species were processing grains by grinding them between two stones – the process we call “milling” – as far back as 30,000 years ago [1]. Indeed, as the application of heat to food is essentially a process, one could argue that we’ve been “processing” food for 400,000 years [2]. Food processing is a practice that’s been integral to the evolution of homo sapiens.

Cultural Food Processing

Religious practices and traditions relating to what we eat have exerted key influences on dietary habits, often for very good reason. Take the inclusion of spices in recipes, for example. There’s evidence that the consumption of spicy foods has been associated with cultures rooted in hotter regions. The addition of spices to foods has antimicrobial effects that help to both prevent food spoilage and provide protection to the human digestive system: a crucial benefit to consumers in those regions with higher incidence of pathogenic diseases. Despite recent studies challenging this notion [3], these stomach-led culinary customs have helped to ward off food poisoning [4]. They are evolutionary adaptations and have led to the coining of the term “Darwinian gastronomy”, meaning culinary behaviours that have provided reproductive advantages [5]. The historical importance of the antimicrobial effects of spices in hotter climates is part of a wider cultural influence. For instance, spicy foods can trigger a temporary increase in metabolic rate giving a small rise in body temperature which, in turn, stimulates sweating, helping us to cool off in hotter temperatures [6]. Hot weather also suppresses our appetite, and adding spices to meals stimulates our biological responses to food cues by making them more flavoursome and interesting, increasing our appetite for them. The effects of cultural tradition validate the choice of ingredients, and the characteristic flavours associated with each culinary cuisine has helped to prevent food from becoming boring.

A familiar seasoning used for food preservation is salt. The salting of food has been practised for millennia, a discovery mainly attributed to the ancient Egyptians, though residents of the Shanxi province in China were fighting wars over salt reserves from the salt lake Yuncheng as early as 6,000 BCE [7]. The salting of meat is associated with more temperate climates, and most microbes can’t survive salty environments. In colder regions, food preservation is easier through natural refrigeration from the cold weather, and in hotter climates, traditionally meat was smoked and then dried in the sun to help preserve it. One of the reasons why the salting of food is still widespread today is that humans have a tendency to favour salt flavours; we taste salt and our brains are informed that the food is safe for us to eat.

Numerous historical cultural food processing methods continue to be practised today. In rural South America, for example, some communities still experience pellagra, a condition associated with a deficiency of niacin, a.k.a. vitamin B3. Symptoms of pellagra include inflamed skin, mouth sores, diarrhoea and dementia. In these regions, maize is a staple food for many. Some grains, including maize, need to be processed through nixtamalization, which involves the grain being soaked and cooked in limewater and then hulled. The tough husks are broken down by the alkaline solution and this makes the niacin bioavailable for absorption in the intestines. Unfortunately, in some South American cultures, nixtamalization isn’t practised and has resulted in a prevalence of pellagra in people of these cultures even today. Nixtamalization is a crucial process in the production of tortillas, hominy and other maize-based breads, foods traditional to many South American cultures, and where these are regular staples, pellagra has been prevented [8]. In other regions of the world, white flour is fortified with niacin, which, along with access to a more varied range of foods, helps to stave off pellagra.

Defining Processed Foods

Of course, few of us associate milling and cooking with food processing. We’re aware that there are different types of “processed food”, and I doubt many of us think of bread, cheese and packaged mixed salad when we hear the term. However, “ultra-processed foods” (UPFs) is a phrase that’s increasingly entering common usage. There doesn’t, however, appear to be a universally accepted definition of UPFs. One attempt is NOVA: a food classification system that categorises food according to the extent and purpose of food processing, rather than in terms of nutrients [9]. Here’s a summary of each group:

Group 1: Unprocessed or minimally processed foods

Edible parts of plants, animals, fungi and algae after separation from nature. Processes are limited to removal of inedible or unwanted parts, or methods like drying, grinding, roasting, boiling, fermentation, pasteurisation, refrigeration, chilling and freezing. These processes are designed to preserve natural foods, to make them suitable for storage, or to make them safe or edible or more pleasant to consume.

Group 2: Processed culinary ingredients

Ingredients such as oils, butter, sugar and salt are substances derived from nature by simple processes to make durable products suitable for use in recipes to prepare, season and cook Group 1 foods and to make them varied and enjoyable. They are not meant to be consumed by themselves, only in combination with Group 1 foods.

Group 3: Processed foods

Foods such as bottled vegetables, canned fish, fruits in syrup, cheeses and freshly made breads are made essentially by adding salt, oil, sugar or other substances from Group 2 to Group 1 foods. Additional processes include various preservation or cooking methods, and, in the case of breads and cheese, non-alcoholic fermentation. Most have two or three ingredients, and are recognisable as modified versions of Group 1 foods, edible by themselves or, more usually, in combination with other foods. The purpose of processing is to increase the durability and shelf life of Group 1 foods, or to modify or enhance their sensory qualities.

Group 4: Ultra-processed foods

UPFs are formulations made mostly from substances derived from foods and additives, with little, if any, intact Group 1 food. They include soft drinks, packaged snacks, reconstituted meat products and pre-prepared frozen dishes. Ingredients may include sugars, oils, fats or salt, but also other foodstuffs that have been directly extracted from foods, such as casein, lactose, whey and gluten. Group 4 items are derived from further processing of food constituents, such as hydrogenated oils, hydrolysed proteins, maltodextrin and high-fructose corn syrup. Food may include additives like preservatives, antioxidants and stabilisers, or those used to imitate or enhance the sensory qualities of foods, such as colours, flavours, sweeteners and processing aids. A multitude of processes are used to combine the ingredients into the final product including those with no domestic equivalents, such as hydrogenation, extrusion and moulding. The overall purpose of ultra-processing is to create branded, convenient, attractive, hyper-palatable and highly profitable food products designed to displace other food groups [10].

An Open Mindset

The NOVA classification on the surface seems fair. But does it really let consumers know if a food is “healthy” or, conversely, something with potentially damaging attributes? Tinned mackerel in brine, for instance, is in Group 3, yet it’s an omega-3-rich fish which we’re told to eat more of. A number of human cultures have been pickling vegetables for centuries in order to preserve their qualities, yet, bizarrely, NOVA lumps these nutritional gems into Group 3. For other foods the classification is unclear: for example, canned vegetables look like they might be in either Group 1 or 3 depending on what they’re canned in, tomato purée – a versatile ingredient that packs an antioxidant punch – isn’t either a clear Group 2 or 3, and coconut fat is listed in both 2 and 3.

For centuries, the only ingredients required to bake bread were flour, water, yeast and, possibly, salt. However, a loaf would go stale within a day or two. Traditional households were larger and a mother would bake a fresh loaf each day confident that the whole thing would be devoured by her hungry family before the next morning. Now view the ingredients list of a commercial granary loaf. You’ll see it typically contains a long list of ingredients: wheat flour, water, malted wheat flakes, malted barley flour, toasted wheat, toasted rye, wheat protein, yeast, salt, vinegar, soya flour, sugar, emulsifiers, barley fibre, antioxidants and several added vitamins. These additions mean that the product has a longer shelf life, is more durable for transport and can be accessed by a wider number of people who don’t have to rely on possessing any bread-making skills. Consequently, although the resulting product also means less food is wasted, it would be categorised as an ultra-processed food.

In modern Western society we’re extremely fortunate: we’re presented with a huge range of foods, many of which we simply wouldn’t have access to if it wasn’t for food processing. Moreover, in the developing world, methods of food processing are crucial to allow the exponentially growing populations in these regions to be nourished.

Now, let me be clear: my motivation here is not to wholly dismiss the classification of UPFs; many overly processed foods should rightly be consumed with caution. I merely mean to highlight three important points:

1. Classifications such as NOVA are too literal and should not be relied upon.

2. Such classifications wrongly imply that the more a food is processed, the “worse” it is.

3. Viewing processed foods with a negative mindset is extremely limiting and will, likely, lead you to unnecessarily miss out on some very nutritious foods.

And, of course, there’s increasing pressure for our food system to be more sustainable, meaning many food processing technologies are integral to 21st-century eating.

(Article originally posted on LinkedIn on August 5, 2021)

References:
1. Revedin, A. et al. (2010) ‘Thirty thousand-year-old evidence of plant food processing’, Proceedings of the National Academy of Sciences USA, 107(44), 18815-9.
2. Fuentes, A. (2020) Why We Believe: Evolution and the Human Way of Being, London: Yale University Press, p93.
3. Bromham, L. et al. (2021) ‘There is little evidence that spicy food in hot countries is an adaptation to reducing infection risk’, Nature Human Behavior, 5(7), 878-91.
4. Billing, J. et al. (1998) ‘Antimicrobial functions of spices: why some like it hot’, Quarterly Review of Biology, 73(1), 3-49.
5. Sherman, P.W. & Billing, J. (1999) ‘Darwinian Gastronomy: Why We Use Spices: Spices taste good because they are good for us’, BioScience, 49(6), 453-63.
6. (a) Westerterp-Plantenga, M. et al (2006) ‘Metabolic effects of spices, teas, and caffeine’, Physiology & Behavior, 89(1), 85-91; (b) Whiting, S. et al. (2012) ‘Capsaicinoids and capsinoids. A potential role for weight management? A systematic review of the evidence’, Appetite, 59(2), 341-8.
7. Butler, S. (2013) ‘Off the Spice Rack: The Story of Salt’, (Updated 16 May 2023). https://www.history.com/news/off-the-spice-rack-the-story-of-salt (Accessed 31/07/23).
8. Clay, K. et al. (2018) ‘The Rise and Fall of Pellagra in the American South: Working Paper 23730’, National Bureau of Economic Research. https://www.nber.org/system/files/working_papers/w23730/w23730.pdf
9. Monteiro, C. A. et al. (2016) ‘NOVA. The Star Shines Bright’, World Nutrition, 7(1-3), 28-38.
10. EduChange (2018) The NOVA Food Classification System. Available at: https://ecuphysicians.ecu.edu/wp-content/pv-uploads/sites/78/2021/07/NOVA-Classification-Reference-Sheet.pdf (Accessed 31/07/23).