Food for thought: Why the NOVA food classification system falls short
At first glance the NOVA system of food classification looks sound, but on closer inspection it misses some crucial points.
The tenets of nutrition for good health, by which I was schooled, were based principally upon the balance between the five food groups, discretionary choices, and the quantities and frequency of these in the diet, and the nutrients they contributed. Today, the definition of a healthy diet has broadened to include concepts of sustainability, plant-based foods and the degree of food processing. I do not agree with the generalised opinion that foods, because they come in a can, box or bag and may contain more than five ingredients, are inherently nutritionally lacking or detrimental to health.
Food processing has a very long history. We can think of processing on a spectrum from simple actions such as chopping and grinding through to fermentation and fortification, and all the way to complex industrial methods and cutting-edge research such as the genetic modification of food.
Every one of us has experienced the benefits of food processing such as inhibition of food-borne microbes, preservation, food consistency, flavour enhancement and convenience. Just think of the state of our pantries and kitchens during Covid times without our packaged foods! With processing of foods there may be the use of additives, for example sodium, sugar and saturated fats. In many instances, the use of these ingredients plays a functional role such as in the prevention of spoilage (such as sodium in cheese), providing colour (sugar in the Maillard reaction) and mouthfeel (saturated fat in shortening of pastry).
There is no denying that a core nutrition principle is the consumption of whole foods. However, as many foods have had some processing, how does the advice to limit processed foods translate to the consumer in a practical way that helps with reduction of diet-related disease such as obesity? As processing encompasses such a wide range of activities, the key challenge is categorising foods to help consumers make healthy diet choices.
A system that is rapidly gaining attention and credence among some academic and public health communities is NOVA. The NOVA system considers the level of food processing and the number of ingredients and additives in a food as an index of food quality.
The four classes of foods in the system are:
- Unprocessed or minimally processed (eg whole foods, fresh or frozen fruits, vegetables, meat, eggs, milk, and grains with no additives)
- Processed culinary ingredients (eg plant oils, animal fats, starches, sugars, salt)
- Processed (eg canned or bottled vegetables, fruit, meats, legumes)
- Ultra-processed (eg breakfast cereals, savoury/sweet snacks, confectionery, carbonated soft drinks, ready-to-eat/prepared foods).
It is the alleged excess consumption of ultra-processed foods (UPFs) linked to an increased incidence of obesity and other diseases that has caught the attention of health authorities such as WHO/FAO and countries such as Brazil and, recently, Canada that have incorporated this concept into dietary policies and guidelines.
There is not a week that goes by that some scientific article will examine the relationship between UPFs and an indicator of health outcomes. The number of articles on the subject is mounting at a rapid rate. What is worth noting is that many of these associations (not correlations) are based upon observational studies. To date there is only one randomised control trial (a study type considered of high calibre as it reduces bias) which is frequently referenced, comprising a sample size of 20 people, and which linked energy intake, body weight and weight gain with intake of UPF.
However, the study could not determine the mechanism for this effect. Likely reasons purported by the authors, and which other articles reference, that link obesity to the intake of these foods include their wide availability, relatively low cost, convenience, high energy density, high palatability and ease of consuming quickly (less chewing is required).
A major limitation of the NOVA system is that it ignores the nutritional value of the food and therefore misrepresents many foods which do have a positive nutritional profile and can contribute to a healthy diet, such as breakfast cereals, wholegrain bread and soy milk, to name a few. Other weaknesses include the changing definition of UPF since its inception, which as a result is open to multiple interpretations. Newer definitions highlight fortification and ingredients not usually used in domestic food preparation such as soy protein isolates.
NOVA also fails to recognise the improved population health outcomes from the prevention of nutrient deficiencies through fortification, or the positive contributions of food processing, formulation and additives in ensuring the safety, nutritional adequacy, quality, preservation and extended shelf life of food, or that homemade foods (often with more than four ingredients), may not differ from the same foods manufactured by a food business that would be classified as UPFs.
Before public health nutrition policy and strategies incorporate food processing as a parameter to assess diet quality, and places further pressure upon the food industry to explain and justify the processes and technologies it uses, further research and insights are needed that demonstrate that the use of NOVA by consumers will result in a better diet quality, and better health outcomes. The generalised recommendations that UPFs should be eliminated from the diet is impractical and does not acknowledge that these foods vary in their nutrient profile, energy density and food properties.
There seems little benefit from the use of the NOVA classification. However, we shall see in the coming months how this shifting paradigm of food quality is addressed in the review of the evidence that will underpin the upcoming review of Australian dietary guidelines.
- This article was first published in the October issue of Inside FMCG magazine. Subscribe to the quarterly magazine for more in depth interviews, features and analysis. (https://insidefmcg.com.au/shop/)