What does “complete” actually mean on a dog food label?
In the UK, a dog food labelled “complete” must provide all the nutrients your dog needs to survive. That’s protein, fat, carbohydrates, fibre, vitamins, and minerals in the right ratios for the stated life stage (adult, puppy, senior). The formulation has to meet the nutritional guidelines set by the European Pet Food Industry Federation (FEDIAF), which is the industry body that sets the standards EU and UK regulators follow.
Complete means complete. Your dog could, in theory, eat nothing but that food for their entire life and stay healthy. Whether they’d enjoy that is a different question, but nutritionally, the claim means the food stands alone.
According to FEDIAF guidelines, a complete dog food must contain minimum levels of 11 essential amino acids, specific ratios of calcium to phosphorus, adequate levels of vitamins A, D, and E, and a full complement of B vitamins. The food must also provide enough energy density to maintain a healthy body weight when fed at the recommended portions.
The legal requirement comes from the UK Animal Feed Regulations 2020 (which replaced EU Regulation 767/2009 after Brexit). If a food carries the word “complete” on the label, the manufacturer is legally responsible for backing up that claim with nutritional analysis. Trading Standards can test products and pursue action against companies that fail to meet the standard.
What is complementary dog food?
Complementary dog food (sometimes called “supplementary” food) is designed to be fed alongside other foods. It does not, on its own, provide everything your dog needs. The label will say “complementary” or “complementary pet food,” and it may also say “for supplementary feeding only.”
That doesn’t mean complementary food is bad. A lot of perfectly decent products fall into this category. Mixer biscuits, dental chews, many wet food pouches, and most treats are complementary. They’re not meant to be a dog’s only nutrition source.
The problem comes when owners don’t realise the difference. If you buy a tin of dog food that says “complementary” and you treat it as a complete meal, your dog will develop nutritional deficiencies over time. The food might look and smell like proper dog food, and your dog will probably love it, but it’s missing essential nutrients.
The Pet Food Manufacturers’ Association (PFMA) is clear on this: complementary foods must be clearly labelled as such. But in practice, the wording can be small, printed on the back, and easy to miss if you’re in a hurry at the supermarket.
How to check the label properly
The most important word to look for is “complete.” If it’s there, on the front of the pack, you’re buying a standalone food. If it says “complementary,” “supplementary,” or doesn’t make any nutritional claim at all, it’s not a complete food.
Here’s what to check:
Front of pack: Look for the words “complete” or “complementary.” In the UK, this declaration is required. The manufacturer must state the category clearly.
Back of pack: You’ll find a more detailed statement. Something like “This is a complementary pet food. Feed alongside a complete food to ensure a balanced diet.” If you see that sentence, you know you need to add something else.
Feeding guide: Complete foods have feeding guides based on your dog’s weight. Complementary foods might have serving suggestions, but they won’t claim to provide full nutrition on their own.
Ingredients panel: This won’t tell you directly whether a food is complete or complementary, but it can give you clues. If the ingredients list is very short and looks like it’s missing vitamin and mineral sources, there’s a reasonable chance it’s complementary.
All About Dog Food has a useful feature where they label every reviewed product as either complete or complementary. If you’re ever unsure about a specific brand, check their database.
What complementary food lacks
The specific nutrients missing from complementary food vary by product. But there are some common gaps that show up again and again.
Vitamins and minerals: This is the big one. Many complementary wet foods are essentially just meat and gravy. Meat is great for protein and fat, but it’s not a complete nutritional profile. Calcium, zinc, iron, vitamin E, and various B vitamins are often below required levels without supplementation.
Calcium: Meat is naturally low in calcium. If you’re feeding a complementary meat-only product without a calcium source, your dog’s bones and teeth will suffer over time. Puppies fed on complementary food without calcium supplementation are at real risk of developmental bone disease.
Fibre: Many complementary foods are very low in fibre because they’re primarily meat-based. Without adequate fibre, dogs can develop digestive issues including chronic diarrhoea and poor stool formation.
Essential fatty acids: While meat contains some omega-6 fatty acids, omega-3s (particularly EPA and DHA) are often missing unless the food specifically includes fish oil or similar sources.
The PDSA reports that one of the most common dietary mistakes owners make is feeding complementary food as a complete diet. They see a tin of meat at the shop, assume it’s proper dog food, and feed it exclusively. Over months and years, this causes real harm.
Common complementary foods in the UK
You’ll find complementary products everywhere: supermarkets, pet shops, online. Some of the most common types:
Mixer biscuits: Products like Harringtons Mixer or similar plain biscuit products are explicitly complementary. They’re designed to be mixed with wet meat to create a balanced meal. On their own, they’re carbohydrate-heavy and lacking in protein and micronutrients.
Meat-only pouches and tins: Some wet food products, particularly budget lines and those sold in multipacks at supermarkets, are complementary. They look like proper dog food but they’re essentially seasoned meat. Pedigree Chum Original in tins, for instance, has complementary versions alongside its complete products. The difference isn’t always obvious at a glance.
Treats and chews: Obviously complementary. No one’s feeding their dog an exclusive diet of dental sticks (hopefully). But it’s worth remembering that treats should make up no more than 10% of your dog’s daily calorie intake according to the British Veterinary Association (BVA).
Rraw meat and bone products: Many raw feeding products sold as individual components (like plain minced chicken, tripe, or bone) are complementary. They’re ingredients for a DIY raw diet, not complete meals. Some raw brands do sell complete formulas, and these will be clearly labelled as such.
Toppers and meal enhancers: Products designed to be sprinkled over or mixed with your dog’s regular food are almost always complementary. Things like bone broth, freeze-dried sprinkle-ons, and gravy-style toppers. They add flavour and some nutrients, but they’re not nutritionally complete.
How to mix complementary and complete food safely
If you’re feeding a complementary product alongside a complete food, there are a few rules to follow so your dog actually gets a balanced diet.
Rule one: the complete food should be the base. Think of the complete food as your dog’s main meal and the complementary food as the garnish. The complete food provides the nutritional foundation. The complementary food adds variety, flavour, or texture.
Rule two: don’t exceed 10-20% complementary. If your complementary food makes up more than about a fifth of your dog’s daily intake, you risk diluting the nutritional balance of the complete food. Keep complementary portions small. A spoonful of complementary mixer on top of a bowl of complete kibble is fine. Half and half is not.
Rule three: count the calories. Complementary food has calories. Those calories add to the calories from the complete food. If you’re adding complementary wet food to a full portion of complete kibble, you’re feeding too many calories. Reduce the kibble portion to compensate.
Rule four: be careful with DIY raw mixing. If you’re combining raw meat (complementary) with complete kibble, be aware of the hygiene implications. Raw meat carries bacteria. If you’re mixing it with kibble that then sits in the bowl for hours, you’re creating a bacterial breeding ground. Serve, let your dog eat, then wash the bowl. Don’t leave raw-mixed food out all day.
Rule five: don’t mix two complementary foods and assume they become complete. Two incomplete things don’t make a complete thing. If you mix complementary meat with complementary mixer biscuits, you still might not have a nutritionally balanced diet. The minerals and vitamins missing from both products are still missing. The only way to create a balanced diet from scratch is to formulate it properly with the right ratios of every nutrient, which is what pet nutritionists do when they design complete foods.
Why this distinction matters more than you think
The consequences of feeding complementary food as a complete diet depend on how long it goes on and what your dog’s life stage is.
For adult dogs, the effects are gradual. A few weeks of complementary-only feeding won’t cause obvious problems. But over months, you’ll start seeing signs: dull coat, low energy, weight loss or gain, poor stool quality, and eventually more serious issues like weakened immune function and bone density loss.
For puppies, the effects are much faster and more serious. Growing dogs need precise amounts of calcium, phosphorus, and specific vitamins for bone and joint development. A deficiency in calcium alone can cause permanent skeletal deformities. Puppies fed on complementary food are at genuine risk of nutritional osteodystrophy, a painful condition where bones don’t develop properly.
Senior dogs are also vulnerable. Older dogs often have reduced absorption efficiency, meaning they need even better nutrition from their food to stay healthy. Feeding a senior dog a complementary diet is asking for trouble.
The PDSA estimates that around 40% of dogs in the UK are fed diets that their vets consider inadequate in some way. Misunderstanding the complete vs complementary distinction is a significant contributor to that statistic.
Can complementary food ever be a dog’s main diet?
Only with careful planning and professional guidance. Some raw feeders construct complete diets from complementary components by following specific recipes developed by veterinary nutritionists. This works, but it requires genuine expertise and regular monitoring.
If you’re feeding a combination of raw meat, bone, organ, vegetables, and supplements in proportions that together meet FEDIAF standards, that’s a complete diet assembled from complementary parts. The key word is “together.” Each individual component is complementary. The combination, if properly formulated, is complete.
But this is genuinely hard to get right without help. If you’re interested in this approach, consult a veterinary nutritionist or use a professionally formulated recipe. Don’t guess. Your dog’s health depends on the math being correct.
For the vast majority of owners, buying a properly formulated complete food is simpler, safer, and usually cheaper than trying to build a balanced diet from complementary parts.
How manufacturers get away with confusing labels
To be fair to the pet food industry, the regulations do require clear labelling. The word “complete” or “complementary” must appear on the pack. But the reality is that many owners don’t know what to look for, and the packaging doesn’t always make it obvious.
Some brands use design tricks that blur the line. A complementary product might be packaged almost identically to the same brand’s complete version. Same colours, same logo, same font. The only difference is one word on the back of the pack. If you grab the wrong one off the shelf, it’s an easy mistake to make.
Supermarket own-brand ranges are particularly confusing. Many supermarket dog foods have both complete and complementary versions in the same range. The complementary version is often cheaper, which makes it an attractive choice for budget-conscious shoppers who don’t realise they’re buying an incomplete product.
The cheapest dog foods on the market are sometimes complementary products marketed to look like complete foods. The low price should be a clue, but many owners assume they’ve found a bargain.
What the experts say
The veterinary consensus is clear: feed a complete food as your dog’s staple diet. Use complementary products as treats, toppers, or occasional additions, but don’t rely on them for primary nutrition.
The BVA recommends that all dog owners check the label and choose a food that’s labelled as complete and appropriate for their dog’s life stage. They also recommend consulting your vet if you’re unsure about any dietary change, particularly for puppies, pregnant dogs, or dogs with health conditions.
The PDSA goes further, warning that feeding an incomplete diet is one of the most preventable causes of dietary illness in UK dogs. Their veterinary teams regularly see dogs with nutritional deficiencies that could have been avoided by reading the label and choosing the right product.
Wet food: complete vs complementary in practice
The complete vs complementary distinction shows up most often in wet food, and that’s where most confusion happens. Many popular wet food products in UK supermarkets come in both complete and complementary versions.
A complete wet food will typically include a broader range of ingredients: meat, cereals or alternative carbohydrate sources, vitamin and mineral supplements, and often some vegetables. The complementary version might be just meat, perhaps with some gelling agent for texture, and that’s it.
If you’re buying wet food on a budget, check every product before it goes in your basket. Don’t assume that every tin or pouch in the dog food aisle is complete. Some of the best-selling wet food products in the UK are complementary, and many owners have no idea.
The wet vs dry debate is a separate question. Both complete wet and complete dry foods are nutritionally valid. The problem only arises when you buy complementary wet food thinking it’s complete.
Price comparison: complete vs complementary
Complementary foods are often cheaper than complete foods, and that’s part of the appeal. A tin of complementary meat might cost 60p while a comparable tin of complete food costs 90p. That 30p difference adds up over a month of feeding.
But here’s the thing. If you’re buying complementary food and then also buying a complete mixer to go with it, your total cost might actually be higher than just buying a complete food in the first place. The apparent saving on the complementary product disappears when you add the cost of the complementary mixer or whatever else you need to balance it out.
Budget complete dog foods from brands like Harringtons, Wagg, and Skinners often work out cheaper per day than a complementary-plus-mixer combination. They’re also guaranteed nutritionally balanced, which takes the guesswork out of feeding.
If you’re looking for the cheapest complete options, check out that guide. There’s genuinely no need to cut corners with complementary food when complete options exist at very low price points.
Honest verdict: what should UK owners do?
This is simple, really. Buy complete food for your dog’s main meals. Read the label every time you try a new product, even if it’s the same brand in a different variety. Keep complementary foods to a maximum of about 10-15% of your dog’s daily intake, and count those calories.
If you’re currently feeding a complementary food as your dog’s only food, don’t panic, but do switch. Transition gradually over a week: start replacing 25% of the complementary food with a complete product, then 50%, then 75%, then 100%. Your dog’s digestion will adjust without drama.
The bottom line is that the pet food industry makes both complete and complementary products for good reasons. Complementary foods have their place: treats, training rewards, toppers, and variety. But they should never be a dog’s sole or primary nutrition source. The label tells you everything you need to know. Read it.
FAQs
Can I feed my dog complementary food every day?
Yes, as long as it’s a small portion alongside a complete food. Treats and toppers are fine daily. The issue is feeding complementary food as the only food. Keep complementary portions under 10-15% of total daily calories and you won’t run into problems.
How do I know if my current dog food is complete or complementary?
Check the front of the pack for the word “complete” or “complementary.” Then check the back for a more detailed statement. If you’re still not sure, check the brand’s website or look the product up on All About Dog Food, which categorises every product it reviews.
What happens if I’ve been feeding complementary food to my dog?
Don’t panic, but do make a change. Book a vet check if your dog has been on a complementary-only diet for more than a few weeks, especially if they’re a puppy. Then transition to a complete food over 7-10 days. Most dogs recover well from short-term nutritional gaps.
Are mixer biscuits a complete food?
No. Mixer biscuits are complementary. They’re designed to be combined with wet meat to create a balanced meal. Feeding mixer biscuits alone will not give your dog adequate nutrition. The protein, vitamin, and mineral content is too low.
Is raw dog food complete or complementary?
It depends on the product. Many raw food brands sell both complete and complementary lines. Their complete recipes include the right balance of meat, bone, organ, and plant matter. Their complementary products might be plain minced meat or single-protein options. Check the label every time.
Common scenarios where owners get caught out
Scenario one: the supermarket multipack. You buy a tray of 12 pouches of what looks like proper dog food. The packaging is bright, the branding is familiar, and there’s a picture of a happy dog on the front. You don’t notice the small text saying “complementary pet food for supplementary feeding.” Your dog gets this as their only food for a month. By the end of that month, they’ve been slowly developing nutritional deficiencies that might take months to reverse.
Scenario two: the pet shop recommendation. You ask a shop assistant for a good wet food, and they hand you a popular brand’s complementary product because it’s on promotion. The assistant might not know the difference, or might assume you’re planning to mix it with something else. You go home, open the pouches, and feed them exclusively because no one told you otherwise.
Scenario three: the online review trap. You read reviews of a dog food product online, and everyone says their dog loves it. The reviews don’t mention that it’s complementary, and the product page doesn’t make it obvious. You order a bulk pack and feed it as a complete diet. Your dog loves it (of course they do, it’s basically pure meat), but they’re not getting a balanced diet.
Scenario four: the rescue dog transition. You adopt a dog from a rescue and the rescue gives you a bag of the food the dog has been eating. If the rescue was feeding a complementary product (either through ignorance or because they were adding other things), you might continue feeding it the same way at home without realising it needs to be paired with something else.
Complementary food and the raw feeding community
Within the raw feeding community, complementary products have a different role. Many raw feeders use complementary products as components of a DIY diet. A complementary mince (plain chicken, beef, or tripe) might be one element of a broader feeding plan that also includes bone, organ, and vegetable components.
Some raw feeding brands specifically design their products as complementary ingredients for this reason. They’re selling you a building block, not a finished diet. The labelling reflects this, and the expectation is that the buyer knows what they’re doing.
If you’re a DIY raw feeder who understands the nutritional requirements and how to meet them, complementary products are perfectly useful. If you’re new to raw feeding and buying complementary products because they look like raw food, you need to do your homework before relying on them as your dog’s main diet.
The PFMA publishes guidelines on raw feeding that include recommended ratios of meat, bone, organ, and vegetable matter. These are worth reading if you’re considering a DIY approach. Alternatively, many raw food brands sell complete raw diets that are already formulated to meet FEDIAF standards.
Wet food trays: the biggest trap for UK owners
In UK supermarkets, complementary wet food is everywhere. Pedigree, Butcher’s, Winalot, and many supermarket own-brands sell complementary tins and pouches alongside their complete products. The packaging looks almost identical. The price difference might be just 10-20p per pack. It’s incredibly easy to pick up the wrong one.
The most reliable way to check is to look at the nutritional analysis on the back. A complete wet food will typically show a full profile: protein, fat, fibre, ash, and moisture at minimum. A complementary wet food might only list protein and fat, or it might show a very limited nutrient profile. If the calcium, phosphorus, and vitamin content aren’t listed, there’s a reasonable chance it’s complementary.
Many complementary wet foods are essentially meat in jelly or gravy. They provide protein and fat but lack the calcium, fibre, and micronutrients that a dog needs for long-term health. Tasty, yes. Nutritious on its own, no.
If you’re unsure about a specific product, the All About Dog Food database is the quickest way to check. Every product is categorised as complete or complementary, and you can search by brand name.