ARE ALL ULTRA-PROCESSED FOODS BAD?

Ultra-processed foods (UPFs) are often portrayed as universally unhealthy. However, a 2025 critical review, published in the Proceedings of the Nutrition Society, argues that this simple message overlooks an important point: the NOVA classification focuses on how foods are processed/formulated, without adequately considering their nutritional value and health effects.

The NOVA food classification system divides foods into four groups, defined according to the extent and purpose of food processing/formulation:

• Group 1: Unprocessed foods and minimally processed foods. This includes whole foods including plant foods (fruits, vegetables, legumes, wholegrains), meat, fish, eggs, milk and whole foods extracted directly from nature or minimally processed by methods such as drying, crushing, grinding roasting, pasteurising, freezing and vacuum packaging.
• Group 2: Processed culinary ingredients. This includes ingredients like fats (oils, butter, lard), sugar, vinegar and salt that are rarely eaten alone but used to season/cook other foods. They may contain additives used as preservatives (e.g. oils with added antioxidants; salt with added anti-humectants).
• Group 3: Processed foods. This includes foods which have undergone simple modifications using traditional methods such as canning, pickling, curing, smoking or fermentation. Examples include canned/bottled vegetables preserved in brine, whole fruit preserved in syrup, canned fish preserved in oil, some cured meats, freshly made breads and simple cheeses.
• Group 4: Ultra-processed foods (UPFs). This includes foods that have often been through many processing steps, and which are also often formulated to contain colours, flavours, emulsifiers and other additives, often added to make products palatable or hyper-palatable. Examples include soft drinks, many packaged snacks, confectionery, packaged breads, sweetened breakfast cereals, and ready-to-eat meals.

The problem with this classification, according to the author of this review, is that foods can receive the same NOVA classification despite having very different nutritional profiles. Some UPFs, such as sugar-sweetened beverages and certain snack foods, are best avoided or limited as they contain little nutritional value and are associated with poor health outcomes. However, the UPF category includes a diverse range of foods, including some wholegrain breakfast cereals, commercial breads, yoghurts, fortified plant-based milks and other convenient foods that may provide valuable nutrients and may have neutral effects or be associated with more favourable health outcomes.

The review also points out that small formulation differences can shift a food from one NOVA category to another without meaningfully changing its nutritional value. Two similar popcorn products, for instance, may be classified differently simply because one contains added flavours or colours, while the main ingredients (corn, oil and salt) are the same.

Research on the health impact of UPFs is also less clear than headlines sometimes suggest. Higher overall UPF intake has been associated with an increased risk of cardiovascular disease, type 2 diabetes, high blood pressure and obesity. However, when researchers examine different types of UPFs separately, the findings vary considerably. Sugar-sweetened drinks and processed meats show the most consistent links with poorer health, and we have known this for many decades, prior to the invention of the NOVA system. In contrast, some breads, breakfast cereals, dairy foods and plant-based milks have shown neutral or beneficial associations. These findings show why it is misleading to treat all UPFs as equivalent when it comes to nutrition and health.
There are also limitations in the way UPF research is conducted. Many studies rely on food frequency questionnaires that were not designed to record specific food brands, ingredients or processing methods that would allow researchers to distinguish between processed/formulated and home-prepared versions of similar foods.

The author of this paper has published a more recent article titled Ultraprocessed food research and scientific discourse where he argues for strengthening scientific rigour in ultra-processed food research.

The key messages from the current review are:

• Processing is only one aspect of a food; nutritional quality matters too.
• The NOVA-Group 4 (UPF) category includes foods with very different ingredients, nutrient profiles and health effects, so a blanket message to avoid every food in the NOVA-Group 4 (UPF) category may be too simplistic.
• Criticising the NOVA system does not mean that all foods classified as UPFs are healthy; it is important to also consider the nutritional characteristics of a food, including added sugars, starches, sodium, saturated fat and fibre content.
• Some UPFs can provide a cost-effective source of essential nutrients, especially for economically disadvantaged populations, and their longer shelf-life can help reduce food waste.
• A more useful classification system would combine information about processing/formulation with nutrient content.

• Louie JCY. Are all ultra-processed foods bad? A critical review of the NOVA classification system. Proc Nutr Soc. 2025.
• Louie JCY. Ultraprocessed food research and scientific discourse. Nat Food. 2026.

Dr Kate Marsh is an is an Advanced Accredited Practising Dietitian, Credentialled Diabetes Educator and health and medical writer with a particular interest in plant-based eating and the dietary management of diabetes and polycystic ovary syndrome (PCOS).

Contact: Via her website www.drkatemarsh.com.au