Complete vs complementary feed: is all wet food complete?

Complete feed vs complementary feed can look like a tiny wording difference on a can of wet food, but it actually tells you a great deal about how that food should be used. From the outside, a can of wet food may look like a perfectly ordinary dog dinner. Meat. Organs. Broth. Maybe a few vegetables or herbs.

The dog happily eats it, the owner reads the ingredient list and thinks, “This looks much more like real food than kibble.” But then there is one small phrase on the back of the can: complementary feed. Another almost identical can says: complete feed.

And I completely understand why those two terms may not mean much to people at first. You often cannot tell the difference just by looking at the food. A complementary feed may be made from excellent-quality meat and look fantastic in the bowl. A complete feed may even look less appealing to the owner when they read the ingredient list.

But “complete feed” and “complementary feed” are not judgments about which food is better. They tell you something else: whether that particular product can be used as the dog’s entire daily ration or whether it needs to be part of a larger whole.

Wet food is not automatically complete feed

Under European Union feed legislation, complete feed means feed that, because of its composition, is sufficient for a daily ration. Complementary feed, by contrast, is intended to be used together with other feeds so that the total daily ration is sufficient.

“Wet food” mainly describes the form of the food and its high moisture content. It does not tell you whether the food contains all the nutrients a dog needs in the right amounts. In exactly the same way, dry food can be either complete or complementary.

So the first thing to look for on a can of wet food is not the meat percentage or the attractive picture. First check whether it says “complete feed” or “complementary feed”.

What does “complete feed” actually mean?

According to FEDIAF, a complete feed that is used over a prolonged period as the sole source of nutrients must meet the nutritional needs of the species and life stage for which it is intended. That includes protein and fat, but also essential amino acids, fatty acids, minerals, vitamins and the relationships between them.

Take a simple example. A can might contain nothing but excellent-quality beef. From a dog’s perspective, that may be a very good ingredient. But the fact that a food is 100% meat does not automatically make it a nutritionally complete daily ration.

For example, the calcium-to-phosphorus balance in muscle meat may be unsuitable if a dog eats nothing but that for months or years. It may also fail to provide sufficient amounts of certain trace elements, vitamins or essential fatty acids.

That does not make meat a bad food. It simply means that a good ingredient and a balanced ration are not the same thing.

Complete feed does not automatically mean ideal food

One camp says: “If the package says complete feed, everything is fine.” Another says: “If the food is made from real meat, why add anything at all?” In reality, both statements can be too simplistic.

The complete-feed designation gives us very important information about nutritional completeness. But it does not automatically tell us that the food is ideal for every dog. And a beautiful, meat-rich ingredient list does not automatically mean the dog is getting everything needed for long-term health.

Complete feed means nutritionally complete. It does not automatically mean optimal for every individual dog.

A dog may have a food intolerance or a health condition. They may be a very active sport dog or, at the other end of the spectrum, an older dog with a low energy requirement. A puppy’s needs differ from those of an adult dog. Two dogs of the same body weight can have very different energy needs. So in addition to the words “complete feed”, we always need to look at whom the food is intended for.

Complementary feed is not inferior food

The term “complementary feed” can sound as though the product is somehow incomplete or lower quality. That is not what it means.

Some complementary feeds are designed to be mixed with another food and may provide a substantial share of daily energy. Others are intended to add specific nutrients. Still others include treats and chews. What they have in common is that they are not intended, on their own, to cover the entire daily ration.

A complementary feed can therefore be an excellent product. The problem begins only when we use it in a way it was not designed for. For example, when a dog is fed the same canned complementary feed as the main food day after day simply because the dog loves it and the ingredient list looks good.

One day is unlikely to matter. A few days are not usually a catastrophe either. Nutritional imbalance becomes important mainly when this type of feeding becomes the dog’s normal long-term diet.

A shortage of calcium, trace elements or vitamins may not cause any visible sign the next morning. The dog may initially look completely healthy. The effects of nutrient deficiencies or inappropriate nutrient ratios can develop over time. Balance is especially important for a growing puppy.

The whole ration can be balanced even when each individual component is not complete feed

I do not want this article to leave you with the message: “The easiest option is to feed only packaged complete food and everything else is dangerous.” That is not what I am saying.

A daily ration can be fully balanced even when its individual components are not complete feeds on their own. A well-formulated home-prepared diet, a balanced raw diet or a menu that combines different food components can successfully meet a dog’s needs. The question is whether the whole ration has been thought through, not whether every individual item in the bowl carries the words “complete feed”.

Balance needs to be assessed across the entire diet, not from a single ingredient.

Can you add fresh food to a complete feed?

If my dog eats a complete feed but I add meat, egg, kefir, vegetables, broth or a complementary feed, have I ruined the balance?

This is where two slightly different approaches meet. Conventional veterinary nutrition advice often uses an approximate ten-percent rule: unbalanced extras should provide no more than about ten percent of daily energy. This is a conservative rule of thumb, not a magical threshold beyond which a dog’s diet suddenly becomes unbalanced.

Some integrative and practical feeding sources use a more flexible guide. Guidance on adding fresh food has suggested that around a quarter of a commercial diet can be replaced with fresh whole foods without every added component having to be complete feed in its own right. As the fresh portion grows beyond that, the diversity of the whole ration, mineral balance and correct proportions between components become increasingly important.

So I would not treat ten percent as a magical boundary. A spoonful of kefir, an egg, sardines, a little meat or some vegetables do not automatically destroy the balance of a complete food. The question is the whole bowl: what are we removing, what are we adding in its place, how much of daily energy does it provide, and are the dog’s nutrient needs still being met?

There is no Homeostasis Fairy in the can

Here is another common logic trap. If one part of the bowl is complete feed, it can feel as though that complete feed somehow balances the rest of the menu too. But the status of complete feed does not transfer to the other foods.

Let’s take a simple mathematical example. If a dog’s daily energy requirement is 1,000 kcal and they get 100 kcal from complete feed and 900 kcal from home-prepared food, those 100 kcal of complete feed do not suddenly become a vitamin-and-mineral premix designed to cover 1,000 kcal. If the same complete feed would provide X mg of a nutrient at 1,000 kcal, then 100 kcal of that food provides roughly 0.1 × X mg. The rest has to come from the other 900 kilocalories.

If we really had a Homeostasis Fairy, things would of course be much easier. Before each meal, she would inspect the bowl, take a quick inventory and use her tiny scoop to measure out exactly what that particular dog needs that day.

“There was already plenty of copper from the beef liver today, so I’ll leave mine out. Calcium is a little low? I’ll add some. Enough vitamin D? I’m off duty today. Phosphorus got out of hand? I’ll adjust it right away.”

Unfortunately, the Homeostasis Fairy has not reached the market yet. The food, balancer or other supplement in the container does not analyse your dog’s bowl or change its composition according to what has already been added. It delivers exactly the nutrients it contains, in exactly the amount supplied by the portion the dog eats.

So the question is not only “does this food contain vitamins and minerals?” but “what does the finished ration provide as a whole?” If complete feed accounts for only a small share of daily calories, the rest of the menu has to do the rest of the nutritional work. Balance does not come from one magical component, it comes from the whole bowl.

“Balance over time” does not mean balance months later

If you prepare your dog’s food yourself, every individual bowl does not have to contain all required nutrients in perfectly identical proportions. In integrative and raw-feeding approaches this is often described as “balance over time”.

Integrative veterinarian Judy Morgan describes this for a healthy adult dog as covering the necessary nutrients over several days, with the goal of reaching a complete nutritional profile within about one week at the latest. It does not mean that balance can be postponed for a month, three months or half a year.

Nor does balancing over a week mean that a dog can eat essentially nothing but meat for six days and receive every missing nutrient in one go on day seven. Some nutrient needs have to be met more frequently, and the week’s diet still needs to be built deliberately.

Morgan emphasizes that the “balance over time” approach is intended for healthy adult animals. It should not automatically be applied to puppies or dogs with health problems.

Why can’t you compare the protein and fat percentages in wet food directly with dry food?

Another thing that creates enormous confusion with wet food is protein. An owner picks up a bag of dry food and sees: “Protein 25%.” Then they pick up a can: “Protein 10%.” And think: “There is hardly any protein in this canned food.”

But those two numbers cannot be compared directly because wet food contains a large amount of water.

If a canned food contains 80% water, only 20% dry matter remains. If the analytical protein content is 10% of the product as fed, then on a dry-matter basis the protein content is 10 ÷ 20 × 100, or 50% of dry matter.

Suddenly ten percent does not look quite so low.

That is why, when comparing the nutrient content of wet and dry food, we need to use a dry-matter basis or, when appropriate, compare nutrients per unit of energy. Water changes the appearance of the percentages on the label dramatically.

The same applies to fat

Exactly the same calculation applies to fat. A wet-food label showing 6-8% fat can look very low next to a dry food with 15-20% fat, but those percentages are not directly comparable.

If the wet food contains 80% moisture, it has 20% dry matter. But if the label says 6% fat, that becomes 6 ÷ 20 × 100, or 30% fat on a dry-matter basis. If the fat content is 8%, it becomes 40% of dry matter. So a wet food containing 6-8% fat may not be leaner at all than a dry food containing 18% fat.

If you want to compare wet and dry foods, the formula is simple: dry matter % = 100 – moisture %. Nutrient % on a dry-matter basis = nutrient % on the label ÷ dry matter % × 100.

Converting to dry matter makes the percentages on the label comparable. If we want to know how much fat a dog actually receives for a given amount of energy, it is even more precise to compare fat per unit of energy, for example grams per 1,000 kilocalories.

A higher moisture content is not a bad thing in itself. On the contrary, wet food can provide a significant share of a dog’s fluid intake through food. But moisture does not tell us whether the product is complete feed.

“But it contains vitamins and minerals” does not prove that it is complete feed

A complementary feed may also contain vitamins, minerals or other feed additives. Some complementary feeds are specifically designed to provide a particular nutrient.

So you should not try to guess from the ingredient list alone whether a food is complete. Under the European labelling system, the manufacturer must state whether the product is complete feed or complementary feed.

If that information is difficult to find, I would ask the manufacturer. You can also ask which life stage the food is intended for and whether the manufacturer can provide a full nutrient analysis rather than only the analytical constituents that must appear on the label.

Complete feed is not a quality medal

“Complete feed” does not mean: “This is definitely an excellent food.” It means that the food is formulated to meet the dog’s nutrient needs when used as intended. Those are two very different claims.

When evaluating a food, we may also care about ingredient quality, processing, protein sources, fat quality, digestibility, the dog’s individual tolerance, stool quality, skin, coat, body weight and many other things.

In exactly the same way, the term “complementary feed” is not a red warning label. A high-quality pure meat product can be an excellent part of a dog’s diet. It simply needs other components alongside it.

An egg is an excellent food. Beef is an excellent food. Broccoli is an excellent food. But whether any one of them, by itself, forms a complete lifelong diet is a completely different question. The same applies to a dog’s bowl.

What should you look for on the can and in the whole bowl?

• If you are buying wet food as the main diet, first check whether it is labelled as complete feed.
• If it is complementary feed, check how the manufacturer recommends using it and what it is intended to be fed alongside.
• If you use complementary feed or fresh food as a small part of a complete diet, you do not need to chase every spoonful with a calculator.
• If the additional or unbalanced portion starts to make up a large share of the daily diet, review the entire ration.
• If you prepare food yourself, think about balance for a healthy adult dog over days and up to roughly one week, not over months.
• Puppies, pregnant and lactating dogs, and animals with health problems require especially careful diet planning.

Balance comes from the whole bowl

Do not judge dog food by a single word. Not “premium”. And not “holistic”. Not by the meat percentage. And not even by the words “complete feed” alone.

“Complete feed” answers one very important question: can this food, when used as intended, meet the dog’s daily nutrient requirements?

But after that come the next questions. What is the food made from? How well does the dog tolerate it? Does it suit their life stage, activity level and health status? How much do they actually eat? What else do they get? And what does the whole bowl look like over the course of the day and the week?

Because in the end, dogs do not eat definitions. They eat what we put in their bowls.

Balance is not created by one word on a can. Balance is created by the whole bowl.

Used sources:

• Regulation (EC) No 767/2009 of the European Parliament and of the Council on the placing on the market and use of feed, Article 3 and Article 15. EUR-Lex.
• FEDIAF. Nutritional Guidelines for Complete and Complementary Pet Food for Cats and Dogs, 2025.
• FEDIAF. Nutritional needs of cats and dogs.
• FEDIAF. How wet pet food is made.
• FEDIAF. Chews and treats for dogs.
• Dr. Judy Morgan. Balance Over Time for Dogs, 4 April 2025.
• Whole Dog Journal. Home-Prepared Dog Food. Fresh food addition discussion, including the ~25% practical guideline.
• Canadian Academy of Veterinary Nutrition (CAVN). Dog Treats. VCA Animal Hospitals.

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