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It’s nothing new to demonise food processing. As a student of food science and nutrition, I read on one hand that food processing was necessary, helping to preserve foods and prevent food wastage, while on the other hand, it was a necessary evil that stripped foods of important nutrients. Milling of wheat grains into white flours was a prime example because a large proportion of the vitamins and minerals are in the aleurone layer just under the bran. On the whole, however, food processing had enormous benefits in safety and availability that allowed large cities and civilisations to prosper.

Today, a new system of classifying foods according to four levels of processing takes industrial processing to new heights of fear (Table 1). In this classification, the least processed food is called ‘minimally processed’, while the most highly processed is called ‘ultra-processed’, and the system is garnering support (1).

Table 1. The NOVA Classification of Foods

Category Description
1: Unprocessed or minimally processed Unprocessed or minimally processed Unprocessed: edible parts of plants or of animals, fungi, algae and water
Minimally processed: unprocessed foods altered by industrial processes such as removal of inedible or unwanted parts, drying, crushing, grinding, freezing etc… that do not add salt, sugar or other substances. This group includes minimally processed foods that contain additives that prolong storage life or prevent spoilage by microorganisms
2: Processed culinary ingredients Processed culinary ingredients Substances obtained directly from Category 1 or from nature by industrial processes such as pressing and refining. May contain additives that prolong storage or prevent spoilage.
3: Processed foods Processed foods Products made by adding salt, oil, sugar or other Group 2 ingredients to Group 1 foods using preservation methods such as canning. This category includes breads and cheeses. May contain additives that prolong storage life or prevent spoilage.
4: ‘ultra-processed foods’
‘ultra-processed foods’ Formulations of ingredients, mostly of exclusive industrial use, many requiring sophisticated equipment, such as fractionation, chemical modification, high temperature extrusion, frequent use of additives whose function is to make the final product more palatable (e.g., flavours, colours), or more convenient
Level 4 includes foods that are often referred to as convenience foods, soft drinks, refined starchy foods (e.g., corn chips, potato crisps), processed meat and salt-preserved foods (e.g., bacon and ham). However, this category also includes foods that contain ‘cosmetic’ food additives – flavours, colours and emulsifiers – that are used to make food more palatable and attractive. Foods that combine cheap processed oils, refined sugars, starches and salt belong in this category too, but those containing preservatives are not necessarily considered ultra-processed.
Never mind that grandma made delicious meals and baked goods (cakes and cookies) using Level 2 foods – culinary ingredients – butter, white flour, sugar and salt – her products were freshly prepared and not industrially produced or packaged. Typically, the whole family ate cake or cookies for morning and afternoon tea, not just celebrations.
Monteiro and colleagues are quick to point out that food processing in itself in not the issue. They acknowledge that practically all food is processed and the benefits of drying, freezing, and vacuum-packing are not denied. However, they believe their classification is discriminating and precise, and the identification and definition of ‘ultra-processed foods’ is distinctive and only made possible by use of additives.
They argue that ‘ultra-processed foods’ are therefore almost imperishable and hyper-palatable for consumers and highly profitable (low-cost ingredients and long shelf-life) for manufacturers. Moreover, they maintain that ‘ultra-processed foods’ are also nutritionally unbalanced and liable to be over-consumed. The underlying premise is that these are the foods that gave rise to obesity.
Personally, I am among the many sceptics of the NOVA classification. Like Mike Gibney and colleagues from University College Dublin (2), I see little value. Last year, two years after the death of my 96-year-old mother, I made a nostalgic trip to the rural town called Hay in outback New South Wales, Australia where she grew up. I bought a copy of a book of old black and white photographs taken in town in the 1930s (3), when my mother was a teenager, studying to become a nurse. I was struck by page after page of matronly, buxom, generously sized, stout women (but not men) whose Body Mass Index (BMI) would most certainly have been 30+ kg/m2. Even the children appeared to have plenty of ‘puppy fat’ on their sturdy little bodies.
Seeing these photographs, I was reminded that Australia in the 1900s grew up literally on the sheep’s back. We had over 100 million sheep and fewer than 7 million people. Our fine merino wool was exported all around the world and farming families ate lamb or mutton for breakfast, lunch and dinner. Wheat and sugar were grown domestically and also big export earners.
My grandparents were market gardeners whose fresh fruit and vegetables were irrigated with water taken directly from the Lachlan River. All their food would be considered Level 1 (minimally processed) or Level 2 in the NOVA system. There were no food additives, no industrially produced foods and certainly no supermarkets.
Yet the abundance of food clearly allowed the genetically predisposed to become overweight and obese. Perhaps Australia’s rural population of the 1930s was the first generation of ‘settlers’ to enjoy such a plentiful food supply? Slightly overweight pregnant mothers would have given birth to children at higher risk of excessive weight gain and the cycle of intergenerational obesity was set in train. Perhaps this explains why today Australian rural populations have significantly higher rates of obesity than those living in urban areas.
Read more:
  1. Monteiro and colleagues. ‘ultra-processed foods’: what they are and how to identify them. Public Health Nutr. 2019.
  2. Gibney and colleagues. ‘ultra-processed foods’ in human health: a critical appraisal. Am J Clin Nutr. 2017.
  3. A collection of photographs by Miss Irene Brown from the archives of the Hay Historical Society.

Professor Jennie Brand-Miller holds a Personal Chair in Human Nutrition in the Charles Perkins Centre and the School of Life and Environmental Sciences, at the University of Sydney. She is recognised around the world for her work on carbohydrates and the glycemic index (or GI) of foods, with over 300 scientific publications. Her books about the glycemic index have been bestsellers and made the GI a household word.