Complete vs Complementary Cat Food: What the Label Really Means (UK)
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Two cat foods can sit side by side on the shelf, both full of real chicken, and only one of them can be fed on its own. The difference is a single word on the label: complete or complementary.
In short. Complete food has everything your cat needs as a daily diet on its own. Complementary food doesn’t. It’s designed to be fed alongside other food, like a topper, treat or mixer.
The official definitions
UK pet food labelling comes from European feed law (Regulation 767/2009), which the UK kept after Brexit, and the industry follows the FEDIAF labelling code.
- Complete pet food is food that, because of what’s in it, is enough for a daily ration on its own.
- Complementary pet food contains a lot of certain ingredients but is only enough for a daily ration when fed with other foods.
Pet food packs have to say which type they are, using wording like “complete feed” or “complementary feed”.
Why it matters
If you feed a complementary food as your cat’s only food for a long time, your cat could miss out on nutrients it needs. That’s not because the food is “bad”. It simply wasn’t designed to be a whole diet.
Complementary doesn’t mean low quality. Some of the most meat-heavy tins on sale are complementary, because they’re mostly meat or fish without the full balance of added vitamins and minerals.
How to check your cat’s food
- Look for the word. It’s usually on the back or side of the pack, near the feeding guide: “Complete food for adult cats” or “Complementary food for cats”.
- Check the life stage. A complete food might be made for kittens, adults or seniors. A food labelled complete with no life stage given is meant to be complete for all life stages.
- Read the feeding guide. Complete foods give daily amounts by your cat’s weight. Complementary foods often tell you to feed them with a complete food.
Real examples
- Applaws tins: UK retailers sell most Applaws tins and pouches as complementary. Applaws’ dry food is sold as complete.
- AATU wet food: AATU says its wet recipes are nutritionally complete.
- Thrive Complete: as the name says, sold as complete.
Brands can change recipes and labels, so always check the pack you actually buy.
Can I mix complete and complementary food?
Yes. Many owners use complementary tins as a tasty topper on a complete food. A good rule of thumb is that most of your cat’s daily food should be complete, and complementary food should be the extra. If your cat has a health condition, ask your vet how to balance their diet.
Related: Best wet cat food UK · Best cat food UK
Sources: Regulation (EU) 767/2009 definitions as quoted in the FEDIAF Code of Good Labelling Practice for Pet Food; brand and UK retailer listings, checked 8 October 2026.