Should we turn our backs on ultra-processed foods?

Historically, processed foods have been valued for their microbiological safety, affordability and longer shelf life, so why is it that the perception of so-called ultra-processed foods (UPFs) is changing so rapidly?

Let’s start with a simple explanation of the term ‘ultra-processed foods’. The term was introduced by a group of Brazilian researchers, led by Professor Carlos Monteiro, who proposed a new classification of foods that was not based on the nutritional composition of foods, but rather on the level of processing.^{01 02}

The NOVA classification proposed by the researchers assigns foods into four groups based on the extent and purpose of processing:

• Unprocessed or minimally processed
• Processed culinary ingredients
• Processed
• Ultra-processed foods (UPFs)

Foods that contain additives such as colours, flavours and non-sugar sweeteners (or which include ingredients that cannot be found in a normal kitchen cupboard) are considered to be ultra-processed. Monteiro and his co-researchers emphasise that ‘common attributes of ultra-processed products are hyper-palatability, sophisticated and attractive packaging, multi-media and other aggressive marketing to children and adolescents, health claims, high profitability, and branding and ownership by trans-national corporations.’⁰³

Many research studies have applied the NOVA classification, and reported associations between the consumption of ultra-processed foods and adverse health outcomes.^{04 06} These associations made the headlines, but causality and the mechanisms that explain these associations are unclear.^{07 08} So the story is not as simple as we may be led to believe.

Limitations of the NOVA classification

There is no gold standard for applying the NOVA classification, and despite its widespread use, it has some severe limitations.^{09 13} A very important constraint is that it is difficult to consistently classify products into the NOVA groups, as demonstrated by authors Braesco et al,¹⁴ who invited over 150 French food and nutrition specialists to complete an online survey in which they assigned foods to NOVA groups.

The authors concluded that ‘Although assignments were more consistent for some foods than others, overall consistency among evaluators was low, even when ingredient information was available… This finding raises questions about how functional NOVA is in its current form. It should also spur reflection on the reliability of conclusions from epidemiological studies that use NOVA as well as on NOVA’s ability to guide public health policy or provide useful information to consumers.’ .¹⁴

Ultra-processed foods are a very diverse group of products

Relating the type and degree of food processing to health cannot be done independently of the nutritional composition of the final food product. The UPF category includes a wide variety of food products, such as wholegrain breads, infant formula, fortified ready-to-eat breakfast cereals, dried soups, flavoured yoghurt and teas. The category also includes products with potentially high levels of salt, sugar and fat, such as crisps, biscuits and pizzas. Most ‘junk’ foods (products high in calories, sugar, salt and/or fat) are classified as ultra-processed foods, but not all UPFs are ‘junk’ foods. Energy- and nutrient-dense foods exist across different levels of food processing.^{10 15 16}

Some UPFs are important sources of micronutrients

Many UPF foods and beverages such as wholegrain or enriched breads and cereals, or flavoured milk, contribute significantly to daily micronutrient intakes.^{11 17} Avoidance of these products may not address obesity but could decrease intake of important nutrients.^{11 18 19}

Processed foods are thus nutritionally important for many diets. They also contribute to food security (access to food) and to nutrition security (access to nutrients).¹⁷ However, some processed foods can also be high in nutrients that should be limited, such as sugar, salt and fat (known as HFSS foods). These HFSS products should be consumed in moderation.

On the other hand, foods and beverages that are minimally processed are not by default healthy either. Think about home-made biscuits, pies or pizza, which may be high in calories, sugar, salt and/or fat, but are not classified as UPF.

Food processing at home versus in a factory

Foods are not only processed in a factory, but also at home. The main difference between processing foods at home or in a factory is the scale and the equipment used. Often the actual process is quite similar, but the scale and equipment used in factories makes the process more efficient and the product safer and more affordable.

Usually, the main concern regarding the ingredients used in food factories is the class of ingredients called additives. Food additives are ingredients important for maintaining and/or improving the safety and freshness (preservatives), taste (sweeteners), texture (emulsifiers, stabilisers, thickeners) and appearance (colours) of foods.

Additives are also used at home and in restaurants. Examples are leavening agents to raise dough, vanillin sugar to add flavour, gelling agents such as pectin and gelatine, and cornflour to thicken sauces. The difference is that at an industrial level there is a larger toolkit with more diverse ingredients at hand to develop products. Not all ingredients listed on the package may sound familiar, but they all play an important role in the product.

It is also important to note that all food additives are safe. The safety of food additives is evaluated by international and local organisations such as Codex Alimentarius and the European Food Safety Authority. Food additives are stringently regulated to ensure they are used in the right way, and that consumers are well informed. The level of many additives in food is regulated, and a number of additives are permitted only for certain foods.

The important role of ultra-processed foods in the food system

The current global food system is neither fair nor inefficient. One billion people around the world are hungry, while two billion are obese or overweight. In the meantime, one-third of the total food produced globally is wasted. The Covid-19 pandemic, wars and rapid climate change have made the issue more evident and serious. Urgent changes are needed to be able to feed the world in a more sustainable and healthy way. Ultra-processed foods are part of the solution.

When it comes to the environment, many people may think that consuming fresh food is more sustainable than consuming processed, packaged foods, but processing and packaging can be of great value. They help to improve access to food by ensuring a continuous supply throughout the year, and also to extend product shelf-life, thereby reducing food loss and waste.

A recent study based on data from the United Kingdom showed that ‘on a per 100 kcal basis, ultra-processed and processed foods had, in general, a lower nutritional quality, lower greenhouse gas emissions, and were cheaper than minimally processed foods, regardless of their total fat, salt and/or sugar content. The most nutritious, environmentally friendly, and affordable foods were generally lower in total fat, salt, and sugar, irrespective of processing level.²⁰ The researchers pointed out that ‘food processing may play a relevant role in food system sustainability and ensuring food security, primarily when agriculture cannot provide fresh food. Moreover, processing can often convert non-edible raw materials into edible, safe and nutritious foods and aid in preserving and increasing the shelf-life stability of products.²⁰

Food processing thus plays an essential role in mitigating nutrition insecurity and feeding the world sustainably.^{21 22} It remains, however, important to continue to improve ultra-processed foods in terms of nutritional composition and environmental impact.

Calls to avoid processed and ultra-processed foods reject the need for processing of food and nutritional security.¹² And yet, from a public health perspective, there is a call to limit the consumption of all UPFs, irrespective of their nutritional composition.

Some national Food Based Dietary Guidelines have already incorporated the recommendation to limit the consumption of UPFs (as defined by NOVA). But how realistic is this recommendation, given that in some countries more than 50% of daily calories are derived from UPFs? Not everyone has access to a variety of whole foods. We should also remember that not everyone has the knowledge, food preparation skills, time or money to prepare and consume only minimally processed foods daily.¹⁷

Food Based Dietary Guidelines that caution against the consumption of all UPFs will most likely confuse the population and hence not achieve their purpose.

Elimination of all UPFs from the diet, irrespective of their nutritional quality, would be akin to throwing the baby out with the bath water. This will not help fix the broken food system but may serve to worsen the existing disparities in food security.