How to Read a Dog Food Ingredients Label: What the Percentages and E-Numbers Actually Mean

Key Takeaways

• UK dog food labels list ingredients in descending order by weight, but fresh meat listed first can sometimes contribute less protein than a concentrated meat meal listed further down once moisture is removed

• The 'crude' in crude protein, crude fat, crude fibre and crude ash refers to the testing method used, not the quality of the ingredient

• A food can only be called 'complete' if it meets FEDIAF nutritional guidelines for a sole diet, while 'complementary' food is not designed to be fed alone

• E-numbers are simply regulatory codes covering colours, preservatives, antioxidants and thickeners, so spotting one on a label does not automatically mean an ingredient is artificial or harmful

• Understanding these labelling rules helps owners see past marketing terms like 'premium' or 'natural', which carry no legal definition in UK pet food labelling

Picking up a bag of dog food and actually understanding what's printed on the back can feel like reading a different language. Percentages, crude this, crude that, mysterious E-numbers tucked between preservatives and vitamins - it's a lot to take in for anyone just trying to feed their dog well. Learning to decode these labels properly is one of the most useful skills a dog owner can pick up, because it turns a confusing wall of small print into a genuinely useful shopping tool.

Pawcredible, a British dog food and treats brand based in Chipping Norton, spends a lot of time talking to dog owners about exactly this kind of label confusion, and argues that the word "complete" on a bag doesn't mean much if a dog's body can't actually use what's inside it. That's a fair point to sit with before getting into the detail, because percentages and additive codes only tell part of the story. This guide breaks down what the numbers and letters actually mean, so every bag or pouch can be judged on substance rather than clever packaging.

What Those Percentages Really Mean

Every UK dog food label carries a "Composition" section, and by law, ingredients must be listed in descending order by weight. Whatever appears first is present in the largest quantity, and whatever appears last is present in the smallest amount. This single rule is the foundation for reading any label sensibly, because it shows exactly what a recipe is built around.

There's a catch worth knowing, though. Ingredients are weighed before cooking or processing, which means a fresh meat listed first might actually contribute less usable protein than a concentrated meat meal listed further down, once the fresh meat's natural moisture has cooked away. A recipe topped with a high fresh chicken percentage can sound impressive, but once that chicken loses its water content during processing, the real protein contribution might be smaller than a concentrated chicken meal positioned lower on the list. This is precisely why the composition list and the analytical constituents further down the label need to be read together, not in isolation.

Front-of-pack claims also follow strict percentage rules under the UK's Quantitative Ingredient Declaration, known as QUID. Any ingredient highlighted on the front - such as "rich in chicken" or "with beef" - legally requires a percentage figure somewhere on the pack. Understanding the thresholds behind these claims changes how they read entirely:

• A "with chicken" claim can legally appear on packaging when chicken makes up as little as 4% of the recipe.

• Using an ingredient's name without the word "with" (for example, calling a product simply "Chicken" rather than "with chicken") requires that ingredient to make up at least 26% of the recipe.

Once these thresholds are known, front-of-pack claims stop being a shortcut and start being a prompt to flip the bag over and check the small print properly.

Decoding the Composition List

Beyond percentages, the order and naming of ingredients in the composition list reveals a lot about a recipe's quality. Vague terms like "meat and animal derivatives" or "poultry" give very little away about what's actually inside, since they can legally cover a wide range of animal parts and species. Named, specific ingredients such as "chicken," "lamb," or "salmon" give a much clearer picture of what a dog is eating and make it far easier to spot potential allergens or sensitivities.

It also helps to look at how many separate protein sources appear, and where they sit relative to starches, oils, and additives. A recipe with a clearly named protein at the top, followed by recognisable vegetables, fats, and a short list of vitamins and minerals, tends to be easier to trust than one padded out with generic fillers or a long string of unfamiliar chemical names. Reading composition lists side by side across a few products, rather than trusting the front-of-pack branding, is one of the simplest habits for building confidence at the pet food aisle.

Understanding Analytical Constituents

Sitting just below the composition list, the "Analytical Constituents" section gives the actual nutritional breakdown of the finished food. This is where crude protein, crude oils and fats, crude fibre, and crude ash are declared as percentages, and it's arguably more useful than the composition list for judging nutritional value, since it deals in measured outcomes rather than raw ingredient order.

What 'Crude' Really Means

The word "crude" often puts people off, sounding like a warning sign for low quality. In reality, it's simply the scientific term for the standard laboratory method used to measure each nutrient's total amount in the food. Crude protein testing, for example, measures total nitrogen content and calculates protein from that figure - it doesn't say anything about how digestible or usable that protein actually is for a dog. Seeing "crude" on a label is a sign of standard, regulated testing, not a red flag about the food itself.

Normal Ranges for Protein, Fat, Fibre and Ash

Knowing what "normal" looks like makes these figures far more useful when comparing products. For most adult dogs, generally accepted healthy ranges look like this:

• Crude protein: roughly 22-32%

• Crude fat: roughly 10-18%

• Crude fibre: roughly 2-5%

• Crude ash: typically under 8%

A food sitting well outside these ranges isn't automatically wrong, since working dogs, puppies, and seniors all have different needs, but it's worth asking why a particular recipe deviates from the norm. Ash, in particular, often gets overlooked, yet a persistently high ash percentage can be worth raising with a manufacturer, since it reflects the mineral content left after all organic matter is burned off during testing.

Complete Versus Complementary Food

One of the most important words on any pack is either "complete" or "complementary," and the difference matters enormously for how a dog is actually fed. A food labelled "complete" meets FEDIAF (European Pet Food Industry Federation) nutritional guidelines for use as a sole diet, meaning it covers the minimum and maximum levels of protein, fat, vitamins, and minerals appropriate for a dog's life stage. FEDIAF guidelines are the accepted industry standard behind every "complete and balanced" claim seen on UK and European pet food packaging.

A food labelled "complementary," by contrast, does not meet those full nutritional standards on its own and is not designed to be fed as the only source of nutrition. Treats, toppers, and many raw mixers fall into this category, and there's nothing wrong with that, provided owners understand the food needs pairing with a complete diet rather than replacing it entirely. Mixing up these two labels is a genuinely common mistake, and one that can quietly lead to nutritional gaps if a complementary product is fed as though it were a full meal.

E-Numbers: Friend or Foe?

Few things on a pet food label cause as much anxiety as a string of E-numbers. The "E" simply stands for Europe, and the numbering system exists purely to keep additive labelling consistent across different countries and languages. Every E-number represents a substance that has been through rigorous safety testing before being approved for use in food across the EU and UK, which includes pet food.

How the E-Number Categories Work

E-numbers are organised into ranges according to what job they do, and knowing the ranges takes a lot of the mystery out of a label:

• E100-E199 covers colours

• E200-E299 covers preservatives

• E300-E399 covers antioxidants and acidity regulators

• E400-E499 covers thickeners, emulsifiers, and stabilisers

Spotting a number in the 200s doesn't automatically mean a preservative is harsh or artificial, and a number in the 100s doesn't automatically mean a colour is unnecessary. The category simply tells a reader what function the ingredient performs in the finished product.

Natural Versus Synthetic Additives

Here's the detail that surprises a lot of people: an E-number says nothing about whether an ingredient is natural or synthetic. Vitamin C, for instance, carries the code E300, a nutrient that occurs entirely naturally and simply happens to fall under the same labelling system as artificial dyes and preservatives. The presence of an E-number is a regulatory identifier, not a verdict on quality.

That said, there's a reasonable case for caution around certain additive categories. Some E-numbers have been linked to hyperactivity in children, though no equivalent studies currently exist for dogs. Even without direct evidence of harm in dogs, avoiding artificial colours and flavours where possible remains a sensible, low-risk approach for owners who prefer to keep a dog's diet as close to real food as they can.

Spotting Meaningless Marketing Buzzwords

Some of the most persuasive words on a dog food bag carry no legal weight whatsoever. Terms like "premium," "super-premium," "gourmet," and even "natural" have no formal definition in UK pet food labelling, which means they can legally be applied to almost any product, regardless of what's actually inside. A bag covered in these words might well be excellent, but the words themselves prove nothing on their own.

The real test is always the composition list and analytical constituents underneath the marketing language. Training the eye to skip past bold buzzwords and go straight to the ingredient order and nutrient percentages is one of the fastest ways to separate genuinely good recipes from ones simply dressed up to look premium. If a manufacturer's confidence in a product doesn't show up in a clear, specific ingredients panel, that's worth noticing.

Bioavailability Matters More Than Labels

Reading a label carefully answers most of the "what's in this food" questions, but it can't fully answer "can my dog actually use this." That's the concept of bioavailability - how well a dog's body can absorb and put a nutrient to work, rather than simply passing it through the digestive system unused. A recipe can list an impressive-sounding protein percentage and still deliver poor real-world results if that protein comes from a source a dog struggles to digest efficiently.

This is where gentle processing methods matter. Freeze-drying, for instance, preserves natural enzymes, amino acids, and nutrients far more effectively than heavily processed, high-heat manufacturing, which is one reason freeze-dried raw ingredients are increasingly discussed alongside bioavailability. According to Pawcredible, food that isn't bioavailable simply passes through a dog's system rather than nourishing it, which is why the brand builds its freeze-dried raw recipes and its freeze dried raw coated kibble around ingredients chosen for what they deliver nutritionally, rather than how impressive they look on a percentage breakdown. Pawcredible frames this as the real gap in most pet food conversations - plenty of labels look complete on paper, yet the ingredients inside them may never get properly absorbed.

Ultimately, understanding percentages, analytical constituents, and E-numbers gives any dog owner the tools to compare products fairly and spot inflated claims. Pairing that label-reading skill with an eye for bioavailable, minimally processed ingredients is what turns careful shopping into genuinely better nutrition. For dog owners ready to put this knowledge into practice, trying freeze-dried raw dog food options is a sensible next step for a diet built on real, traceable ingredients.