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Category: Choosing dog food

How to compare dog foods in the UK – reading labels, wet vs dry and what the evidence says about grain-free diets.

  • Grain-Free Dog Food: What the Evidence Says

    Grain-free dog food is widely available, and since 2018 it has also been linked in the news with a heart condition called dilated cardiomyopathy (DCM). This guide explains what “grain-free” means, what the US Food and Drug Administration (FDA) actually said about its investigation and what it didn’t, and why changes to your dog’s diet are best discussed with your vet.

    What grain-free means

    “Grain-free” is a marketing description, not one of the legal labelling categories such as “complete” or “complementary”. It means the recipe doesn’t contain grains. When the FDA classified foods in its investigation, it counted a product as grain-free if it didn’t contain corn, soy, wheat, rice, barley or other grains (FDA investigation page). A grain-free food still has to be labelled complete or complementary, with a composition list and analytical constituents like any other dog food. See our guide to reading a dog food label.

    Why some owners choose grain-free

    Owners choose grain-free foods for different reasons. Some believe grains are “fillers”, some suspect their dog reacts to grains, and some simply prefer the recipe or the brand. We describe these reasons here without endorsing them.

    On the “filler” point, the World Small Animal Veterinary Association (WSAVA) says that nothing in a pet food is truly a filler, and that every ingredient must have a nutritional purpose. It explains that cereal grains mostly provide energy but also provide essential nutrients and fibre, and that dogs can digest properly cooked grains. It adds that there is no evidence to show grains are harmful, as long as the overall diet is complete and balanced (WSAVA FAQs and myths).

    The FDA investigation into diet and canine DCM

    DCM is a disease of a dog’s heart muscle that results in an enlarged heart. Historically, it has been linked mainly to a genetic predisposition in certain breeds. Here is what the FDA has said, in its own words where possible, with dates:

    • July 2018: the FDA announced it had begun investigating reports of DCM in dogs eating certain pet foods, many labelled “grain-free”, which contained a high proportion of peas, lentils, other legume seeds (pulses) and/or potatoes as main ingredients.
    • June 2019: in its third status report, the FDA said the potential association between diet and DCM “is a complex scientific issue that may involve multiple factors”.
    • December 2022: the FDA said it did not intend to release further public updates “until there is meaningful new scientific information to share”. It noted that adverse event numbers, by themselves, “do not supply sufficient data to establish a causal relationship with reported product(s)”.
    • The FDA’s questions and answers (page current as of August 2024) say that most diets in the reports had legumes and pulses high in their ingredient lists, and that these included both grain-free and grain-containing formulations. The FDA says legumes and pulses have been used in pet foods for many years, “with no evidence to indicate they are inherently dangerous”. It also says it “does not know the specific connection between these diets and cases of non-hereditary DCM” (FDA Q&A on non-hereditary DCM).
    • Recalls: the FDA says it “has no definitive information indicating that the diets are inherently unsafe and need to be removed from the market”.

    In short, the FDA has not said that grain-free food causes DCM. It has said there is a potential association that is complex, may involve multiple factors such as genetics, underlying medical conditions and diet, and isn’t yet understood. Throughout, the FDA has encouraged pet owners to work with their vets, who may consult a board-certified veterinary nutritionist, before making diet changes.

    If your dog shows possible signs of heart disease, the FDA lists decreased energy, cough, difficulty breathing and episodes of collapse as examples. Contact your vet as soon as possible.

    Allergies and sensitivities

    Some owners choose grain-free because they think their dog has a food allergy. Diagnosing a food allergy or intolerance is a job for your vet, not something to settle by switching foods at home. WSAVA notes that the ingredient list may be useful when choosing a food for a dog with a diagnosed food allergy or intolerance. It warns, though, that cross-contamination with ingredients not listed on the label can happen during normal manufacturing. If you’re concerned about how your dog reacts to food, speak to your vet before changing their diet.

    Choosing a complete food, with or without grains

    Whether a food contains grains matters less than the basics:

    1. Is it labelled complete?
    2. Is it intended for your dog’s life stage?
    3. Can you follow the feeding guide and keep your dog at a healthy weight?
    4. Does your vet have any advice for your individual dog?

    WSAVA publishes a checklist for selecting a pet food that you can take to your vet.

    FAQ

    Is grain-free dog food bad?

    The FDA has not concluded that it is. It is investigating a potential, complex association between certain diets, many of them grain-free and high in pulses, and non-hereditary DCM, and it has said it doesn’t know the specific connection. Talk to your vet before changing your dog’s diet.

    Does grain-free food cause DCM?

    This hasn’t been established. The FDA says report numbers alone can’t establish a causal relationship, and that reports have involved both grain-free and grain-containing diets.

    Does my dog need grain-free food?

    Most dogs don’t need a particular grain status. WSAVA says that dogs can digest properly cooked grains and that there’s no evidence they’re harmful in a complete and balanced diet. If you think your dog has a food allergy, ask your vet.

    Grain-free vs grain-inclusive: which should I choose?

    Start with a complete food for your dog’s life stage, whichever type it is, and discuss any concerns, including DCM, with your vet.

    Sources

    Checked on 22 October 2026. This guide summarises official statements and isn’t veterinary advice.

  • Wet vs Dry Dog Food: Differences and How to Choose

    Wet or dry? For most healthy dogs, the honest answer is that either can work, as long as the food is complete and suits your dog’s life stage. The PDSA says that unless your vet has advised otherwise, your dog can have wet food, dry food or a combination of the two (PDSA: your dog’s diet). This guide explains how the formats differ in practice and how to compare them fairly.

    The main differences

    Wet food (tins, trays, pouches) Dry food (kibble)
    Moisture High; much of the weight is water Low
    Amount per day A larger weight of food is usually needed per day, because of the water content. Check the feeding guide. A smaller weight per day. Check the feeding guide.
    Once opened Needs refrigerating, covered, or throwing away Keep in its original bag, sealed, in a cool, dry place
    Comparing labels Analytical constituents are given “as fed”, including the water, so wet and dry percentages can’t be compared directly

    A few points behind that table:

    • Moisture is on the label. UK Pet Food says the label must state the moisture percentage when it exceeds 14% (UK Pet Food labelling factsheet), so you’ll see it on wet foods. Because wet food contains much more water, its protein and fat percentages look lower than a dry food’s, even when the two are similar once the water is taken out. Don’t pick between them on percentages alone. Our guide to reading a dog food label explains each line.
    • Compare cost per day, not per pack. A tin price or a bag price on its own doesn’t tell you what a day of feeding costs. Work out how much your dog would eat per day from each pack’s feeding guide, then compare on that basis.
    • Preference and practicality. The PDSA notes that some dogs prefer to stick to the same food every day, while others enjoy variety, and that the flavour and texture you choose doesn’t matter as long as your dog is happy and the food is complete.

    Mixing wet and dry food

    Mixed feeding is common, and the PDSA says it’s fine. The key is portion size. If you feed a combination, the PDSA says you need to make sure you’re giving the right total amount by looking at the packets and working out portion sizes. In other words, combining foods doesn’t mean serving a full daily portion of each.

    A simple way to do this:

    1. Decide roughly what share of the day’s food will be wet and what share will be dry.
    2. Use each pack’s feeding guide for your dog’s weight to work out that share of a full daily amount. For example, half the daily wet amount plus half the daily dry amount.
    3. Count treats and extras as part of the day’s intake.
    4. Monitor your dog’s weight and body condition, and adjust if needed. Your vet or vet nurse can help.

    Storage and hygiene once opened

    The US Food and Drug Administration’s safe-handling advice for pet food applies wherever you live (FDA: tips for safe handling of pet food and treats):

    • Promptly refrigerate or throw away unused or leftover tinned and pouched food, and cover refrigerated food tightly.
    • Store dry food in a cool, dry place, in its original bag with the top tightly folded down.
    • Wash food bowls and scoops with soap and hot water after each use, and don’t use the bowl as a scoop.
    • Wash your hands before and after handling pet food and treats.
    • Don’t buy packs with visible damage, such as dents, tears or discolouration.

    Always follow the storage instructions on the pack, too.

    Switching food gradually

    Whether you’re moving from dry to wet, wet to dry or to a mix, change gradually. The PDSA advises switching over a couple of weeks and avoiding sudden changes unless your vet advises otherwise, because a sudden change can cause tummy upsets or refusal to eat. Its suggested steps:

    1. Days 1 to 3: give your dog their regular meal, plus a small teaspoonful of the new food on a separate plate or bowl. Don’t mix the foods together.
    2. Days 4 to 10: mix a very small amount of the new food into the old one. If that goes well, slowly increase the new food while decreasing the old.
    3. Days 10 to 14: once your dog is consistently eating the mix for at least a week, start phasing out the old food.

    When to talk to your vet

    • Your dog has a medical condition, or is on a vet-prescribed diet.
    • You notice changes in appetite, drinking, weight or body condition. The RSPCA says that if your dog’s eating or drinking habits change, you should call a vet, as this could be a sign that your dog is ill (RSPCA: a healthy diet for dogs).
    • You’re not sure how much to feed, especially for a growing puppy or an older dog.

    FAQ

    Is wet or dry food better for dogs?

    Neither is better for every dog. According to the PDSA, unless your vet has said otherwise, your dog can have wet, dry or a combination. Make sure the food is complete and suits your dog’s life stage.

    Can I mix wet and dry dog food?

    Yes. Work out portions from both packs’ feeding guides so the total adds up to one day’s food, not a full portion of each.

    Why does wet food show lower protein on the label?

    Because the percentages include the water in the food. Wet food contains a lot more water than dry, so its percentages look lower, and you can’t compare the two labels directly.

    How long can I keep opened wet dog food?

    Follow the instructions on the pack. The FDA advises promptly refrigerating, tightly covered, or throwing away leftover tinned and pouched food.

    Sources

    Checked on 22 October 2026.

  • How to Read a Dog Food Label (UK Guide)

    A dog food label carries more useful information than the front-of-pack picture suggests. In the UK, much of what goes on a pet food label is set by law, so once you know where to look, you can compare foods on the same basis. This guide walks through each part of the label and what it does and doesn’t tell you. For questions about your own dog’s needs, especially if they have a health condition, ask your vet.

    Complete or complementary?

    This is the first thing to check. UK feed law, Regulation (EC) No 767/2009 as it applies in the UK, requires the label to state the type of feed, including whether it is a “complete feed” or a “complementary feed” (Article 15). The same regulation defines them (Article 3):

    • Complete feed is a food that, “by reason of its composition, is sufficient for a daily ration”.
    • Complementary feed is “sufficient for a daily ration only if used in combination with other feed”.

    The PDSA says a balanced diet starts with food labelled “complete”, because that means it contains all the nutrients your dog needs in the correct amounts (PDSA: your dog’s diet). If a food is complementary, it isn’t meant to be fed on its own.

    Life stage and species

    The law requires the label to state the species or categories of animal the food is intended for (Article 17). Many foods also state a life stage, such as puppy, adult or senior. The PDSA advises feeding a food that’s appropriate for your dog’s present life stage, and it notes that a growing puppy needs a complete food suitable for their size.

    Feeding guidelines

    Labels must include instructions for proper use (Article 17), which for most foods means a feeding guide by body weight. Treat this as a starting point, not a fixed amount. The PDSA suggests using the packet guidelines as a starting point and, if your dog needs to lose or gain weight, feeding for their target weight, which might not be their current weight. Weighing portions helps, and so does remembering treats and extras. If you’re unsure how much to feed, ask your vet or vet nurse.

    Ingredients: “composition”

    The ingredients list appears under the heading “composition”, in descending order by weight (Article 17). UK Pet Food’s labelling factsheet explains the two ways ingredients can be listed (UK Pet Food: understanding pet food labels):

    • By category: names laid down by the regulations, such as “meat and animal derivatives”, “cereals” or “derivatives of vegetable origin”.
    • By individual name: for example, “chicken” or “rice”.

    According to UK Pet Food, mixing category names and individual names in the same list isn’t permitted, except for an ingredient that doesn’t fall into any prescribed category, which must be listed by its own name. If the label draws attention to a specific ingredient, for example “with chicken”, the percentage of that ingredient must also be listed.

    The World Small Animal Veterinary Association (WSAVA) adds a useful caution: the ingredient list gives no information on the quality of the ingredients and can be misleading about the overall quality of the food (WSAVA Global Nutrition Guidelines). Use it alongside the rest of the label, not on its own.

    Analytical constituents

    For complete and complementary dog foods, the law requires the label to list analytical constituents for crude protein, crude fibres, crude fat and crude ash (Annex VII). UK Pet Food explains that:

    • these are given as percentages, and moisture must also be listed when it exceeds 14%;
    • “crude ash” represents the mineral content, measured by burning the product, and may also be labelled “incinerated residue” or “inorganic matter”.

    These figures describe what’s in the food as sold. They aren’t targets, and we don’t suggest “ideal” percentages. Wet and dry foods contain very different amounts of water, so their percentages can’t be compared directly. See our wet vs dry dog food guide.

    Additives

    Certain feed additives must be listed under the heading “additives” (Article 15). UK Pet Food notes that:

    • if vitamins A and D are added, their presence and level must be declared;
    • preservatives, antioxidants or colourants that have been added may be declared;
    • if you have questions about additives, contact the manufacturer and quote the batch number.

    Other things the label must show

    • Best before date. The minimum storage life, given as “best before” or “use before” (Article 17).
    • Batch or lot number, for traceability (Article 15).
    • Net weight (Article 15).
    • Name and address of the business responsible for the label (Article 15).

    Marketing words vs legal terms

    “Complete”, “complementary”, “composition”, “analytical constituents” and “additives” are legal labelling terms with set meanings. Many other words on the front of a pack are marketing. UK Pet Food says all information on a pet food label must be truthful and not misleading. Even so, a word like “premium” or “natural” doesn’t tell you whether the food is complete or suitable for your dog’s life stage, so check the statutory information. The European pet food industry body FEDIAF publishes a Code of Good Labelling Practice that explains how terms such as “rich in beef” are used.

    FAQ

    What does “complete” mean on dog food?

    Under UK feed law, a complete feed is one that, by reason of its composition, is sufficient for a daily ration. In other words, it’s designed to be fed on its own as the main diet.

    Why is the ingredient list in categories?

    The regulations allow ingredients to be listed by category names such as “meat and animal derivatives” or “cereals” instead of individual names. UK Pet Food explains that a label can use categories or individual names, but generally not a mix of both.

    What are analytical constituents?

    They are the declared percentages of crude protein, crude fat (oils and fats), crude fibre and crude ash, plus moisture when it’s over 14%. They describe the food’s make-up as sold, not how good it is.

    Can I tell which food is best from the label?

    The label helps you check the basics: complete or complementary, species, life stage and feeding guidance. It can’t tell you whether a food suits your individual dog. If your dog has a health condition, allergies or unexplained changes in weight or appetite, ask your vet.

    Related guides

    Sources

    Checked on 22 October 2026.