What does ultra-processed food mean?
Ultra-processed food is a research category based on how products are made and formulated. It includes foods with very different nutritional profiles, from soft drinks to some packaged wholemeal breads. Use the term as a reason to take a closer look at a product, alongside its fibre, salt, sugar and saturated fat content and how often you eat it.
How the NOVA classification works
The term comes from a system called NOVA, developed by nutrition researchers at the University of São Paulo in Brazil from about 2009 onwards. Most food guidance, including HPB's, sorts food by what it contains, such as sugar, salt, saturated fat and fibre. NOVA sorts food instead by how much industrial processing it has been through and by what has been added along the way.
The system has four groups.
- Group 1 is unprocessed or minimally processed food. Fresh, frozen or dried vegetables and fruit, eggs, meat, fish, plain rice, plain oats, milk, plain yoghurt, legumes and nuts belong here. Washing, freezing, drying, grinding and pasteurising do not move a food out of this group.
- Group 2 consists of processed culinary ingredients, such as oil, butter, sugar, salt and extracted starches. These are typically used to prepare or season meals. Plain flour made by grinding grain belongs with minimally processed foods in Group 1, rather than this group.
- Group 3 is processed food. These are group 1 foods with group 2 ingredients added, usually to preserve them or improve the taste. Canned tuna, canned beans, cheese, salted nuts, cured fish and a loaf made from flour, water, salt and yeast sit here.
- Group 4 is ultra-processed food. These are industrial formulations made mostly from substances derived from food, such as modified starches, hydrolysed proteins, refined oils and sugars, combined with additives a home kitchen does not use. Emulsifiers, colours, flavourings, sweeteners and thickeners are the usual signs.
The ingredient list can help identify an industrial formulation, but length or unfamiliar names alone do not determine its category or health effects. Preservatives, fortification and processing have different purposes. Look at both the formulation and nutritional profile.
Examples from Singapore shops and meals
The groups are easier to picture with local examples.
- Group 1. Rice, kai lan, eggs, a whole fish from the wet market, plain oats, frozen peas, dried soy beans and unsalted peanuts all belong here.
- Group 2. Cooking oil, sugar, salt and extracted corn starch are examples. Plain grain flour is generally Group 1. A product called cornflour may be flour or extracted starch, and its group depends on which it is.
- Group 3. Canned fish or beans with added salt, salted nuts and simple bread made from flour, water, salt and yeast are examples. With tofu and homemade mixed dishes, look at the ingredients and the classification method before you give them a blanket label.
- Group 4. Instant noodles with their seasoning sachet, packaged sliced bread with emulsifiers and preservatives, packet drinks and soft drinks, 3-in-1 kopi mixes, luncheon meat, chicken nuggets, factory fish balls and crab sticks, flavoured yoghurt drinks, sweetened breakfast cereals, biscuits, packaged cakes and most sweetened plant milks all count as ultra-processed.
That last list includes everyday staples, such as the bread for kaya toast and the noodles for a late supper. It also holds many products sold as healthier options. A sugar-free soft drink, a high-protein bar and a low-fat flavoured yoghurt are all formulations, so NOVA places them in group 4.
The two Singapore labels measure something different. Nutri-Grade and the Healthier Choice Symbol are based on nutrients, so a sugar-free soft drink can carry a Nutri-Grade A and still be ultra-processed. Both descriptions are accurate, because they answer different questions.
Why the classification is debated
The classification has drawn sharp criticism from other nutrition scientists, and the points they raise are fair ones.
- It mixes very different foods. Packaged wholemeal bread, a fortified breakfast cereal and a plain soy milk with one emulsifier sit in the same group as sweets, soft drinks and processed meat, so nutrient content within group 4 covers a wide range.
- It is hard to apply consistently. Trained nutritionists asked to classify the same foods have often disagreed, most of all at the line between group 3 and group 4.
- The mechanism is unclear. The harm could come from the additives, the energy density, the softness that makes food quick to eat, the low fibre, or from the fresh food that these products displace. Researchers cannot separate these with the current evidence.
- Most of the evidence is observational. People who eat a lot of ultra-processed food also tend to differ in income, smoking, sleep and activity. Researchers adjust for these differences, but they cannot remove all of their effect.
Defenders answer that the pattern holds across many countries and many outcomes, which is unusual for a result produced by confounding alone. They also point to a controlled feeding study in which volunteers living in a research unit ate several hundred more calories a day, and gained weight, when their meals were ultra-processed, even though the meals were matched for sugar, fat, fibre and salt. Their broader argument is that nutrient labels miss something about the modern food supply.
What health research shows
Large cohort studies in Europe, the Americas and Asia link a higher share of ultra-processed food in the diet with higher rates of obesity, type 2 diabetes, heart disease, depression and death from any cause. A 2024 umbrella review in the BMJ pooled these studies and found the associations were consistent, with the strongest evidence for cardiometabolic disease and early death. These are averages across large groups, and they show association rather than proof of cause.
The picture inside group 4 is uneven. Sugary drinks and processed meat carry the most consistent evidence of harm, and WHO and HPB flagged both long before NOVA existed. Packaged wholemeal bread and plain fortified cereals show weak or no association in several analyses, and in a few they look neutral. Most of the evidence against the category comes from products that older advice already warned about.
Using the idea when shopping and cooking
Treat the idea as a flag that a product needs a second look.
- Read the ingredients and nutrition panel together. Check your regular buys for fibre, salt, sugar and saturated fat. A long or unfamiliar ingredient name is not, by itself, evidence that an ingredient is harmful.
- Rank group 4 by the old rules. Sweetened drinks and processed meat come first, and packaged wholemeal bread comes last. The Nutri-Grade and Healthier Choice labels still help with that ranking.
- Change the anchor of the meal. A bowl of instant noodles with two eggs and a handful of kai lan is a different meal from the noodles alone, even though the noodles are still ultra-processed.
- Cook from basic ingredients when practical. Frozen vegetables, canned beans and convenient whole-grain foods can make that easier. A home-cooked meal can be unbalanced too, so portions, cooking fats and salt still matter.
- Consider the overall pattern. An occasional convenience meal or packet of biscuits does not determine the quality of the whole diet. Improve the meals and drinks you have most often without labelling every processed food as harmful.
Choosing changes that improve your meals
Studies associate diets high in ultra-processed foods with poorer health outcomes, while individual foods within the category differ. Choose changes that improve the overall diet: fewer sugary drinks and processed meats, more fibre-rich foods, and suitable portions. Convenient packaged foods can still help meet nutritional needs.
Anyone with diabetes, kidney disease or a heart condition, and anyone managing weight on medical advice, should talk to their polyclinic doctor or dietitian before reorganising their diet around any classification. Do not stop a medication because your shopping has improved.
A practical next step
Start with changes where the nutrition gain is clear, such as replacing regular sweet drinks with water and adding vegetables or beans to meals. A food’s processing category does not replace a look at the nutrition label.
Sources and further reading
These references explain the guidance and research discussed above. For advice about your own health, speak to a qualified healthcare professional.
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