How the diet of dogs has changed

Most pet foods are a far cry from archetypal diets of dogs and from this mismatch many of the chronic diseases seen today in domestic pets have emerged.

When it comes to diet, the jaw structure of canines gives us an indication of the diet that they evolved to eat and thrive on in the wild. Dogs’ teeth and jaws are adapted to a carnivorous diet with teeth that are designed for capturing and dismembering prey. Nevertheless in the last 12,000 years, through domestication, they have adapted to a more omnivorous diet.

As research into basic and applied nutrition has expanded knowledge of canine nutrition, it is known that a balanced diet must also include an appropriate amount of vitamins, minerals, certain essential amino acids from proteins and essential fatty acids.

In this blog, Amanda Williams, Technical Director and CEO of Cytoplan, who also has a background in veterinary nursing, discusses the natural diet of dogs and considerations when choosing a pet food for your dog.

Skip to Key Takeaways

How dogs have evolved

Dogs have evolved and physically differentiated quite substantially over time. It is undeniable that a St Bernard and a Chihuahua look vastly different, however, this does not mean they are as diverse on the inside.

Despite physical characteristics that differentiate one breed of dog from another, dogs and wolves belong to the same genus (Canis) and share 99.9% of their DNA. These similarities can be identified in notable shared characteristics, like digging and foraging, social behaviours and ways of communicating.

Canids are extraordinarily flexible: they seem to evolve easily into very different forms to suit new niches. Sometimes, unrelated groups will evolve to be of a similar appearance because they are living in similar environments. Why canids are so flexible this way is not known, but it might be the key to the diversity seen in domestic dogs as well. Dogs diverged from grey wolves about 12,000 to 40,000 years ago.  

Protodogs (the original dog types) most likely started following human hunter-gatherers around, eating their rubbish, and gradually getting less shy and aggressive, cuter and more playful. They were tolerated by people because they would have helped with waste disposal, kept away predators, and warned of danger. At some point they started to help with hunting. At first, the hunters would have followed the dogs when they spontaneously went hunting, taking advantage of the dogs’ superior noses. Later on, a more cooperative relationship developed, where the humans and dogs would consciously work as a team, and dogs would be rewarded with a share of the kill.

It is easy to envisage how domestication may have proceeded from this point. Selective breeding would have been unconscious at first – annoying and dangerous animals simply did not survive, whilst favoured ones got extra food and comforts. However, people soon realised that offspring resembled their parents and started to breed favourites deliberately. Human selection effectively has directed the shape, size and characteristics of domestic dogs.

Darwin, reflecting on the evolution of the peppered moth, once said ‘evolution would never be the same twice’ as adaptation is dependent on so many environmental, dietary and other factors that determine speciation, and the development of canids is a good example of multifactorial evolutionary influences.

What should dogs be eating?

The length and function of dogs’ digestive systems also indicates that they were born to eat raw meat and absorb their nutrients primarily from the body parts of their prey with a small additional component of their diet coming from plant matter including grasses, seeds and fruits.

To humans, some of the more ‘undesirable’ parts of an animal are the most delicious and nutritious to canines. In the wild, the first things to be eaten are the internal organs of prey which harbour the most concentrated levels of vitamins, minerals and nourishment. Organs like liver, kidneys and heart are concentrated sources of the fat-soluble vitamins A, D, E and K.

Wolves will consume skin, fur and bones as well as muscle meat in their ancestral diet. In larger prey, the stomach contents may be shaken to remove the bulk of the contents as a natural precautionary instinct, but the lining and contents of the digestive system, rich in natural probiotics and digested food, would be consumed.

The dentition and digestive system of dogs have evolved over the past 12,000 years and domestic dogs are now adapted to a more omnivorous diet. This means that under normal circumstances dogs can meet their nutritional needs by eating a combination of plant and animal foods. The source of the protein and fats is less important than the quality and digestibility of these ingredients.

As research into basic and applied nutrition has expanded knowledge of canine nutrition, it is known that a balanced diet must also include an appropriate amount of vitamins, minerals, certain essential amino acids from proteins and essential fatty acids. Dogs have evolved to use proteins and fats as their primary energy source but they can now also use carbohydrates for energy. Dogs produce enzymes specific for the digestion of starch and sugar which shows that they are capable of digesting carbohydrates.

However, this adaptation has only occurred since the domestication of dogs, and as humans consumed cooked not raw grains during this evolutionary period, dogs are now adapted to cooked grains and are unable to digest raw grains. The early use of grains as food was fraught with risks as wild grains naturally harbour aflatoxins which are poisonous to all species. Humans recognised this early on and hence learned to cook grains to avoid this risk and ‘pet’ animals have similarly adapted. But as grain nutrition post-dates the evolution of the digestive system of both dogs and man there are still uncertainties as to the appropriateness of grains as dietary staples and many people and pet owners choose to leave them out.

What would domestic dogs eat if they were in the wild now?

Raw meat – Raw meat and fats derived from a variety of animals. These provide digestible sources of protein and iron and make up the largest portion of the diet. This is more likely to be from small animals such as rodents, rabbits and birds.

Offal – Organ meat including liver, kidney, heart, spleen and pancreas all contain proteins and deliver a plethora of essential vitamins and minerals.

Bone – For concentrated levels of naturally occurring vitamins and minerals, soft non weight-bearing bones and cartilage are a good natural source of collagen and amino acids, calcium and phosphorus for teeth and bone health, and some zinc. (Care should be exercised if feeding bones to dogs as some types of bones, including cooked bones, are not suitable).

Vegetable and fruit matter – Contains a naturally complete range of vitamins and minerals. Mostly green leafy and coloured vegetables, as well as non-citrus fruits, ideally crushed and pulped to ensure better absorption. Together these supply antioxidants, phytonutrients, fibre and moisture as well as essential vitamins and minerals. As alluded to above, dogs will not naturally eat raw grains.

Other – In the wild this would be fur, stomach lining and organs like eyes and reproductive organs.

Raw food makes sense for a few key reasons:

  • Naturally occurring nutrition in proportions and forms that canids are adapted to use for health
  • None of the ingredients in raw evolutionary diets have been damaged or destroyed (also termed de-natured) or adversely affected by cooking so are at their most nutritionally dense, highest quality and therefore beneficial
  • If prepared correctly, nothing artificial is added to a raw diet as synthetic ingredients have been associated with health problems in pets

Some of the observed health benefits associated with an evolutionary diet are:

  • Superior joint and bone health
  • Strengthened immune system
  • Improved skin and softer, shinier coat
  • Healthier teeth gums and fresher breath
  • Reduced stool volume and odour
  • Enhanced reproductive health
  • Reduced body odour
  • Increased resilience to parasites via enhanced immune function

Addressing the concerns of feeding raw food

Some of the concerns when it comes to feeding dogs raw food are the presence of pathogens, the quality and source of the ingredients, and the processing methods. These concerns are no different to the way humans look at the food they eat.

The number one query when it comes to raw food is, “are there higher levels of bacteria present?” and the answer is yes, absolutely. Unless raw food has been sterilised, which often reduces the nutrient levels as much as the bacterial load, there will most certainly be higher bacterial counts when compared to cooked foods. Are these bacteria bad? Not for pets.

Most particularly if the food used has come from the human food chain which is handled in clean environments and is screened for pathogens such as E. coli, Listeria and Salmonella.

Pets have shorter digestive systems than humans which are designed for foods to enter and exit quickly, not ferment like in a human digestive system. This reduces the time bacteria can sit in the system, replicate and thrive. Furthermore, pets have highly acidic digestive systems which neutralise bacteria and dissolve bone, therefore they are more than capable of handling raw food. Even decomposing food poses little risk to dogs, they often bury bones and food in the garden for a snack a little later on.

But does the handling of raw pet food increase the risk to families? No more so than prepping raw food in our own homes before cooking. It is fundamental that when handling any raw food that safe food handling practices are followed, including washing hands, kitchen tools and workspaces following preparation of raw food to ensure the risk of cross-contamination is eliminated. Ideally use a separate preparation area such as a utility room, not used for family food, and it is suggested that human grade meats are used if preparing the food in the house.

When it comes to quality and processing of food, having the time and ingredient availability to do it yourself is the best quality control. But for some this is not a pleasant task, and nor do they have the time to do this on a daily basis, as much as owners love their pets and want the best for them. But domesticated dogs have adapted over millennia to consume diets provided by their human companions, including foods that have been cooked. So, dogs will do well on a variety of different diets, so long as the ingredients are high quality, digestible and the diet meets the total needs of the dog. However, if changing a dog’s diet, this should be done slowly over a period of a week or longer to allow their digestive system to adapt.

Twenty-five per cent of all households in the UK have one or more dogs as pets. Most dogs in the UK are fed proprietary pet foods which are broadly balanced to meet macronutrient needs. Some of these are well designed with good ingredients and others less so. There are now many more high quality ‘good’ pet foods on the market than there were say 20 years ago. But even the best dry and packed dog foods are very different from the food domestic dogs would eat if they were able to forage and source their own food. Effectively there is a ‘nutrition gap’ for dogs in much the same way as there is for humans (which we have previously discussed in this blog.

Advice to dog owners unable to provide raw or home-cooked food for their dogs is to buy the best premium dog foods (wet not dry, why not the latter is explained later), and then to bridge the gap by adding fresh or raw appropriate vegetables, the occasional apple or pear and topping up with human food-grade supplements. This is the impetus for the new Cytoplan range of supplements for dogs; designed to help bridge the gap between archetypal pet nutrition and commercial pet foods in a pet-friendly, user-friendly way.

Dry vs wet dog food

This is a massive and far-reaching discussion point but below is a flavour of the issues that long-term use of dry foods can create, and the logic behind the issues. Dry food is ‘extruded’ which means the ingredients are cooked at very high temperatures to make the food sufficiently sterile to have a good shelf life. This causes certain issues for dogs:

  1. a) food is devoid of moisture and the protein structure degraded so the content is not something immediately recognisable to a dog’s physiology and metabolic pathways
  2. b) once in the digestive tract, it needs rehydrating back to the moisture content of normal ‘wet’ food; and
  3. c) of perhaps even more importance, dry food is devoid of enzymes. When dry food first emerged in the USA some 40 years ago there was a linear relationship with the increase in pancreatic hyperplasia and other pancreatic problems being diagnosed in pet dogs

The pancreas is the main producer of digestive enzymes, and since dry extruded food is devoid of enzymes (as all of these are killed in the cooking process), the pancreas is forced to produce more enzymes to digest the food and this places a stress on its resources which leads to hyperplasia in the first instance and later on to disease. Natural uncooked food contains enzymes which, by helping food to auto-digest, supports and complements the function of digestive enzymes produced by the body during the digestive process. It is no coincidence that dogs have a comparatively small pancreas, because they are physiologically adapted to eat raw food. Hence it can be questioned if dry food can really meet needs, even though the macro analysis might tick the right boxes on paper.

When changing a dog’s diet, it is advisable to do it slowly over a few days or weeks, mixing their current food with a small amount of the new food and gradually increasing the latter, to allow the digestive system time to adapt.

Key Takeaways

  • The length and function of dogs’ digestive systems also indicates that they were born to eat raw meat and absorb their nutrition primarily from the body parts of their prey with a small additional component of their diet coming from plant matter which includes grasses, seeds and fruits.
  • In the wild, the first things to be eaten are the internal organs of prey which harbour the most concentrated levels of vitamins and minerals and nourishment. Organs like liver, kidneys, and heart are concentrated sources of fat-soluble vitamins like A, D, E and K.
  • A dog’s natural diet includes raw meat derived from a variety of animals; offal (including fur, stomach contents, eyes and reproductive organs); bone and vegetable and fruit matter. (Be careful if feeding bones to dogs, some types of bone including cooked bones are not suitable).
  • The dentition and digestive system of dogs have evolved over the past 12,000 years and domestic dogs are now adapted to a more omnivorous diet and do have digestive enzymes that allow them to digest starchy carbohydrates
  • Although dogs can eat grain, grain nutrition post-dates the evolution of the digestive system of both dogs and man there are still uncertainties as to the appropriateness of grains as dietary staples, and many people and pet owners choose to leave them out.
  • If using commercial dog foods then we would suggest buying good quality wet not dry food and then to bridge the gap by adding fresh or raw appropriate vegetables, the occasional apple or pear and topping up with human food-grade supplements.

If you have questions regarding the topics that have been raised, or any other health matters, please do contact me (Amanda) by phone or email at any time., 01684 310099

Amanda Williams and the Cytoplan Editorial Team

Relevant Cytoplan Products

Doggie Multi – A Food State product high in antioxidant minerals and B-complex vitamins. It is designed to make up for shortfalls in the diets of some dogs who are not foraging and hunting as they would do in the wild.

Doggie Dophilus – A probiotic formula with 6 live strains designed to support digestive health, it includes strains that are most prevalent in domestic dogs which have activity throughout the digestive tract.

Doggie Omega – Formulated to provide an appropriate ratio of the omega-3 and omega-6 fatty acids EPA, DHA and GLA.

Doggie Eat Your Greens – Containing Organic Spirulina and is designed to support dogs who do not have free access to the outdoors. Our Doggie Eat Your Greens has nothing added, nothing removed, no excipients – just 100% pure, clean, organic spirulina. 


Billingshurst, I. (1993) ‘Give your Dog and Bone’. ISBN: 9780646160283.

Billingshurt, I. (2001) ‘The Barf Diet’. ISBN: 9781617811692.

Darwin, C. (1859) ‘On the Origin of Species’.

Hare, B. (2018) ‘How Accurate Is Alpha’s Theory of Dog Domestication?’, Available at:

Lem, K. et al. (2008) ‘Associations between dietary factors and pancreatitis in dogs.’, Journal of the American Veterinary Medical Association, 233(9), pp. 1425-1431.

PDSA (2018) ‘Animal Wellbeing Report’. Available at:

PFMA (2015) ‘Pet Nutrition and Health FAQs’. Available at:

Wayne, Robert K. (1993) ‘Molecular evolution of the dog family.’, Trends in genetics, 9(6), 218-24.

Last updated on 3rd November 2022 by cytoffice


12 thoughts on “How the diet of dogs has changed

  1. Excellent blog Amanda! There is SUCH a difference in observable health status and energy in a dog (or cat) fed a raw or natural diet it is a no-brainer. Bridging the gap with food state supplements is ideal if 100% raw is not possible. Thank you!

  2. I feed my dog and cats raw, dog from 4 months, cat from 8 weeks and kittens from 4 weeks. They love it and I love how healthy they all look.

  3. Thanks so much for this article – really clear and informative, and explains so much about how we’ve manipulated our poor dogs’ diet. Our Tibetan Terrier seems to have a rather sensitive digestive system. We use grain-free dried food mainly, with some extra and tasty moist things, either from our own food or a better quality tinned meat. We tried raw meat and he just wouldn’t eat it. Any advice?

    1. For Barney’s mum, try cooking tasty foods such as beef hearts, chicken (definitely no bones), minced lamb, scrambled or boiled eggs and fish. A slow cooker is great as it slowly cooks the food making it easier to digest. A raw diet is best but a home cooked diet using human grade meat and vegetables comes a very close second. The important thing is not to give any grains including rice as these are hard for your dog to digest. You can cook veg and blend them for a more balanced diet. If your dog needs to put on weight you can include things like sweet potatoes, carrots etc. My 15 year old collie is fed a home cooked diet but she also gets raw, kidney, mackerel (for the omega 3’s) and small amounts of liver. Raw bones such as shin, knuckle or ribs are good for keeping teeth clean. With fussy dogs, you can usually find something they like if you give plenty of choice. Don’t give up – Barney will thank you for it. I hope this is helpful.

    2. Hello,

      Thank you for your comment. The diet you re using sounds like a practical and workable solution. Many dogs do not like raw food if they have not had it from early on in life, and also sudden changes, however healthful, can cause problems, simply because the dog does not have enzymes and bowel bacteria specific to the new food. Although of course they can adapt over time. Domestic dogs do very well on cooked meats and vegetables and if this is easier for you it really is fine.

      If your dog is healthy on what you are doing then I would not worry too much. Maybe err more towards more of the home cooked meat and veg and less of the dry food if you can. But if the sensitivity you describe is a problem then Probiotics could help your dog’s digestion and also improve tolerance to the dry food you are using and give you time to gradually change over to a home cooked diet in total.

      But make change very slowly and see how your dog is faring at every stage and be guided by that. Most dogs do well on either a raw diet if acclimatised to it early in life, or good quality meat and vegetables. I have never been convinced of the benefits or appropriateness of dry foods for either dogs or cats, except of course they are very convenient for owners.

      Best wishes,

  4. Hi. I feed my dog raw. A good quality, complete feed that has everything he needs. Good hygiene is essential, as with any process involving meat. We certainly haven’t had any problems. I do not give him bones because he eats them too quickly, so he gets chews for his teeth. He is in great shape, I would certainly recommend it.

  5. Excellent article . I’ve been feeding raw for 20 plus years. I started with my springer spaniel who seemed to not tolerate dog food and always had runny, blood streaked stools . The moment I started feeding raw it all cleared up – I think she was 6months old when I started. She died aged 17. Her teeth were still clean and white !
    I have since had 4 working golden retrievers. I still have 2. They were all weaned straight onto raw chicken carcasses and meat plus pulverised vegetables.
    I have never experienced any problems . They often get a raw marrowbone to chew on. I would thoroughly recommend this method of feeding. My dogs have lovely coats, don’t seem to get allergies or skin problems. They have good bone and lovely clean teeth.

  6. Great article. The negatives of a dry diet should be more widely publicised. My 6 yo cocker spaniel was diagnosed with DCM in May. After reading widely I immediately changed his diet to a complete raw diet, and soon after, on the advice of a vet nutritionist friend supplemented with taurine. Happy to say that within 2 months Hamish’s cardiologist shared that there was a visible and noticeable physical difference in his heart. I hope to see similar improvement when he goes back in a couple of weeks.

    1. Interestingly, taurine has also helped my 15 year old collie for very different reasons. She has chronic kidney disease and I have her on a home cooked diet with good results. A few months ago she developed petite mal seizures and was having at least 20 a day. I didn’t want to put her on medication as her kidneys are already struggling so after doing the research started her on 500mg taurine twice daily. Within one day of starting the taurine she was down to 2-3 very minor episodes a day and she has stayed at that level. I suspect she was having difficulty metabolising taurine and the symptoms were signs of a deficiency. I am so happy I was able to find such a simple solution to a horrible condition.

  7. I was very interested to read the article about nutrition for dogs. My black Labrador was diagnosed with most aggressive type of mouth cancer 15 months ago. Only treatment suggested by vet was surgery and chemo therapy. I didn’t want her going through the treatment suggested. I have been a healer and therapist for people over 30 years.I decided to treat Bella with natural methods. I ordered vitsmin and mineral supplements and suitable oils from Cytoplan. All the food was organic home cooked food, which I got to fine art. First it felt daunting but after 4 weeks on strictly vegan diet and vegetable puree she was clear of the cancerous tumour. I also gave Bella energy healing . She moved house with us and was healthy until eat ratpoison and died very quickly 4 months ago. The power of nutrition!

  8. Can you recommend a suppliment for my 14 year old Labradoodle, he eats lots of earth, grass goose grass and the seads.

    1. Hello,
      I have spoken with our nutritional therapist and to help you further we would require a little more info. If you could email with the subject FAO Amanda and include the following information – age, diet, medications, and anything else you think may be relevant – i.e. when this started or has it been a constant feature.
      We will then come back to you with some recommendations.

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