Are frozen vegetables ultra-processed? Plain ones — peas, sweetcorn, spinach, green beans, a bag of mixed veg — typically are not. Under the NOVA system freezing and blanching count as minimal processing, which puts frozen vegetables in group 1, the same group as the fresh ones in the chiller. What can move them out of group 1 is anything added on the way into the bag: a cheese or butter sauce, a breadcrumb or batter coating, a seasoning blend built on flavourings. The freezer is not the problem. The recipe printed on the back is.
This one is worth writing up because it is the clearest counter-example we have to the way most people read food labels. Frozen veg looks industrial. It arrives in a plastic bag, made by a factory, kept alive by machinery, with a shelf life measured in months. Every instinct that says “processed” fires at once, and every one of them is pointing at the wrong thing.
What NOVA actually says about freezing
The NOVA classificationsorts food by the extent and purpose of industrial processing rather than by nutrients. Group 1 is unprocessed or minimally processed food. Group 2 is culinary ingredients such as oil, salt and sugar. Group 3 is processed food — group 1 foods with group 2 ingredients added, usually to preserve them or make them ready to eat. Group 4 is ultra-processed food: industrial formulations built largely from derived substances and cosmetic additives.
Minimal processing, in NOVA's own description, covers processes that remove inedible parts or preserve the food without adding anything to it: cleaning, trimming, grinding, drying, chilling, freezing, pasteurising, vacuum packing. Freezing is on the list by name. Blanching — the brief hot-water or steam step that stops enzymes wrecking colour and texture in the freezer — is a form of the same thing. Nothing is added. Nothing is extracted. The pea that comes out of the bag is a pea.
So a bag of plain frozen peas is typically group 1, and so are plain frozen spinach, sweetcorn, broccoli florets and mixed veg. Check the pack — where sugar, salt or a sauce has been added, the classification moves. The plastic, the factory and the long shelf life are not what NOVA is measuring.
Why frozen veg is often the practical choice
There is a second point here that has nothing to do with NOVA group and everything to do with what actually gets eaten. Freezing exists to stop the clock. It is a preservation step rather than a recipe change, which is why NOVA treats it as minimal processing in the first place.
We are not going to quote a vitamin-retention percentage at you, because the honest answer varies by vegetable, nutrient and supply chain, and we have no single figure we would stand behind. So take the rest of this paragraph as our own judgement rather than a research finding. The practical case is simpler: the bag in the freezer is still edible on the Thursday when the fresh spinach has gone to liquid. Eating more vegetables is the goal. Frozen makes that easier and cheaper.
What tips frozen vegetables out of group 1
Walk along the freezer aisle and the picture changes as soon as something is added. Three categories do most of the work:
- Sauces: cauliflower cheese, broccoli in a cheese sauce, peas in butter sauce, creamed spinach. A sauce made from milk, cheese, butter and flour typically reads as group 3. One built on modified starches, emulsifier systems, flavourings or colours typically reads as NOVA 4. The ingredient list is what separates them.
- Coatings:breaded or battered vegetables, crispy coated onion rings, tempura-style products. Batters and crumb coatings are mostly flour, starch and raising agents, which on their own keep a food in group 3. What typically pushes these products into group 4 is what comes with them — flavourings, colours, modified starches or emulsifier systems. Check the ingredient list.
- Seasoning blends:the roasted vegetable mixes and herb-and-garlic bags. If the seasoning is oil, salt, dried herbs and spices, you are still in processed-food territory. If it carries “flavouring”, colours or a yeast-extract-and-additive system used to boost taste, that is a typical group 4 marker.
One distinction is worth being precise about, because it gets muddled constantly. A preservative, an antioxidant or a stabiliser on its own does not make something ultra-processed — under NOVA's own rules those keep a food in group 3. The group 4 markers are the cosmetic additives, flavourings, colours, non-sugar sweeteners and emulsifier systems used to imitate or enhance sensory qualities, plus industrial ingredients rarely found in a home kitchen such as protein isolates, maltodextrin, glucose-fructose syrup and modified starches. We cover that split in more detail in UPF vs processed food.
There is also a separate nutrition point, independent of NOVA group. Sauced and coated vegetable products are often where the salt and saturated fat arrive, and frozen chips and potato products are a different food from frozen broccoli whatever group either lands in. That is a front-of-pack question, not a processing question. Read both.
The twenty-second label test
Turn the bag over and look at what is listed:
- One ingredient:“peas”, “spinach”, “sweetcorn”. Group 1 in almost every reading.
- Vegetables plus kitchen ingredients:oil, salt, herbs, butter, cheese. Usually group 3 — processed, not ultra-processed.
- Flavourings, colours, modified starch, emulsifiers: this is where a bag of vegetables typically becomes NOVA 4.
Or let the app read it for you. Scanning the barcode in Cull's UPF scannershows the NOVA verdict for that specific product alongside its additives and an overall score — handy when the plain bag and the buttered one are stacked in the same freezer and the ingredient lists are printed at the back in six point type. Recipes also change, and a scan reflects the pack in your hand rather than what the category used to contain.
What frozen veg teaches you about the whole scale
This is the useful part. If frozen peas are group 1 and a flavoured frozen vegetable side is group 4, then NOVA is clearly not measuring how industrial a food looks, how long it keeps, or whether it comes in plastic. It is measuring what was done to it and what was put in it.
Oats make the same point from the other direction. As we set out in our post on porridge, the same grain runs from group 1 to group 4 depending on whether it arrives as rolled oats or as a flavoured instant sachet. Frozen veg runs the same span in one aisle. Category is a bad predictor. Ingredient list is a good one.
Two honest caveats before you use any of this too confidently. NOVA is not applied perfectly consistently: when Braesco and colleagues asked 159 and 177 evaluators to classify two lists of foods in 2022, agreement was only fair, with a Fleiss kappa of 0.32 and 0.34. Borderline products — a lightly sauced vegetable side, say — are exactly where coders diverge. And on health, the large observational work is association, not proof of cause. Lane and colleagues' 2024 umbrella review in the BMJ, covering roughly 9.9 million participants, reported associations between higher ultra-processed food intake and a range of outcomes with varying certainty of evidence. The UK's SACN, in its 2023 position statement and its rapid evidence update published on 2 April 2025, found those associations concerning but said the limitations in the evidence mean it is unclear whether processing itself is the cause, rather than these foods simply tending to be high in energy, saturated fat, salt and free sugars.
Which leaves a modest, practical conclusion. Frozen vegetables are one of the easiest non-UPF foods in the shop: cheap, convenient, hard to waste, and minimally processed under NOVA as it is normally applied. Buy the plain bags, add your own butter or oil at home if you want them interesting, and stop feeling guilty about the plastic.
Sources
- Monteiro et al. (2016) — NOVA. The star shines bright, World Nutrition
- Open Food Facts — NOVA groups for food processing
- Braesco et al. (2022) — Ultra-processed foods: how functional is the NOVA system? European Journal of Clinical Nutrition
- Lane et al. (2024) — Ultra-processed food exposure and adverse health outcomes: umbrella review, The BMJ
- SACN (2023) — Position statement on processed foods and health
- SACN (2025) — Processed foods and health: rapid evidence update