The BARF diet is a system of holistic nutrition which is championed by Dr Ian Billinghurst who is an Australian vet. Dr Billinghurst has published several books on health and nutrition. The best known of these is called "Give your Dog a Bone".
In October 2002 I attended the American Holistic Vet Conference in Eugene in Oregon at which Dr Billinghurst gave a paper.
The BARF Evolutionary philosophy is at first glance an attractive one; it seems to be truly natural because it tries to emulate the lifestyle of the dog in the wild.
But, having listened at length and studied his writings I am of the opinion that the BARF theory, like the emperor's new clothes, does not stand up to critical inspection.
By his account, in the late 70s and early 80s Dr Billinghurst was encountering health problems in his own dogs when he fed them on what he considered at the time to be the best commercial foods. (At this time I was advising my clients to avoid all commercial pet foods and to feed cooked brown rice, vegetables and meat.)
When he changed to feeding raw foods Dr Billinghurst found that the illnesses in his dogs disappeared. From this he developed his BARF Diet which stands for "Bones and Raw Food" Diet or "Biologically Appropriate Raw Food" Diet.
To summarise what he is saying:
(1) Most of the health problems which affect pet dogs are due to the fact that they are being fed on commercially prepared pet foods.
(2) The BARF or "Evolutionary" Diet is based on the principle that domestic dogs should be fed on a diet which replicates as closely as possible the diet of the wild dog. According to Dr Billinghurst domestic dogs have been fed on processed (cooked) foods for only approximately 70 years and this is not a long enough time to adapt to cooked foods. To replicate the diet of the wild dog he recommends that pet dogs be fed on a diet based on raw meaty bones and raw vegetables.
Dr Billinghurst insists that because of this evolutionary history the BARF DIET is the ONLY correct way to feed the modern domestic pet dog
According to the BARF theory
(i) The wild dog is a hunter, scavenger and opportunist which has evolved to be capable of thriving on all types of raw food including meat, vegetables, fruit, rotting food, faeces, garbage. The only food type on which dogs will not do well long-term is cooked carbohydrate. Because the dog is not suited to carbohydrate this causes numerous health problems from acute inflammatory disease to chronic degenerative disease.
(ii) Commercially prepared pet foods are based on cooked cereal grains which are mainly carbohydrate and which the dog is not adapted to digest and utilise.
(iii) Cooking kills enzymes in the raw food and this makes cooked food less digestible
(iv) Cooking also destroys some of the nutrients especially vitamins and fats which are present in raw food. When cooked, fats become toxic
It follows from this that the correct Evolutionary Diet for dogs should be based on raw meat and bones, raw vegetables and fruit and raw offal.
The raw vegetables should be ground up to make them digestible. This mimics the churning action which occurs in the digestive tract of the dog's herbivorous prey
Dr Billinghurst also believes that it is normal and healthy for dogs in the wild to eat faeces (of herbivores?). This acts as a probiotic which seeds the intestine with healthy bacteria. Dr Billinghurst stops short of recommending adding faeces to a dog's diet. As an alternative he recommends that his basic diet can be supplemented with yoghurt or non-dairy probiotic (to mimic the probiotic effect of eating faeces)
According to Dr Billinghurst it may be desirable or necessary to supplement with vitamins and oils containing essential fatty acids.
I agree with Dr Billinghurst that much of the disease we see in pet dogs is related to diet, in particular the feeding of the mainstream commercial pet foods. But as he was unfolding his philosophy I got very uncomfortable listening to him. The BARF system was based on the evolution of the dog but my own system of feeding dogs is actually based on human evolution.
Dr Billinghurst went on to describe the health benefits which you see when you stop feeding commercial food and replace with the BARF Diet These health benefits were identical to those we expect to see on my own system.
While listening to Dr Billinghurst I thought "This does not add up".
After several hours of listening I could remain silent no longer so I asked him to comment. His reply was that what I was doing may be an improvement but he was going the whole way.
I think that Holistic Nutrition is a subject which could benefit from an honest debate
to investigate these inconsistencies. Besides, it is a legitimate avenue of scientific enquiry to take a hypothesis or principle to see if it stands up to careful scrutiny.
Let's think first about the evolution of the dog.
According to BARF
Dogs have evolved to eat only raw food, typically bones, raw meat and vegetables. Their ancestors were hunters and scavengers and the change to cooked foods is too recent to allow evolutionary adaptation.
No one is sure how or when the dog became associated with man. Did the modern dog evolve from the wolf or did they both have the same ancestor?
DNA studies of domestic dogs published in Science Magazine in November 2002 suggest that the dog was first domesticated in Asia at least 15,000 years ago and that all domesticated dogs throughout the five continents derive from that original gene pool. If this is correct, dogs travelled with and were traded by man and all modern dogs have been intimately associated with man for at least 15,000 years. This suggests that there have been 3000 -7500 generations of dogs in that time allowing for a new generation every 2-3 years. As valuable commodities, dogs would presumably not have been left to take their chances but would have been cared for including sharing man's food.
Man has had fire for hundreds of thousands of years and has probably been cooking for most of that time so it is likely that dogs were introduced to cooked food at an early stage in its association with man.
In the wild, evolution is a slow process which takes place by Natural Selection (those individuals which are best adapted to their environment will prosper while the less well adapted will eventually disappear).
But it is likely that the development of the domestic dog was not by evolutionary natural selection but by selective breeding. Very early in their association it is likely that man selected and bred those animals which suited his purpose e.g. guarding, hunting, more docile, less independent –even better suited to the food provided by man.
Selective breeding leads to much more rapid change than would happen by Natural selection. The different domestic breeds have been developed within the last 500 years. Anyone involved in breeding knows how quickly genetic characteristics can change.
It may have been the case that the original domesticated dogs were not well suited to human food (although Dr Billinghurst's own assertion that the wild dog is an omnivore, hunter, scavenger, opportunist adapted to thrive on almost anything contradicts this) but we can be sure that those dogs which adapted to eat cooked food as well as raw would survive better than those which could not.
There are practical reasons why the diet of the wild dog is not automatically suitable for the domestic dog.
The modern dog and its lifestyle bear no similarity whatever to the wild dog. We provide shelter in heated houses, they do not have to forage or compete for food, they eat every day, and they have little exercise compared to a wild dog.
Many dogs have dietary sensitivity which means that they need a highly digestible diet, low in protein and low in fat. I can't see how that could be achieved with a BARF diet.
From an evolutionary standpoint the "purpose" of living is to mature rapidly and to reproduce successfully. A long life is not integral to that. But that is not necessarily what we want for our domestic dogs. We probably don't want them to reproduce and we certainly want them to live a long time.
There is another major difference from conditions in the wild. Modern farm animals are reared on high energy diets to make them grow quickly. This means that the fat content of their flesh is very high compared to wild animals or even farm animals a generation ago. Even so-called "lean" meat now has a fat content of as much as 70%. We have to allow for that in any modern feeding regime.
The Carbohydrate Question
According to Dr Billinghurst dogs are not evolved/suited to eating carbohydrate.
This had me digging out the textbook [Strombeck's Small Animal Gastroenterology] to check up on the digestive system of the dog. Once a substance, even one which is detrimental, has been eaten it may be absorbed because the system has no mechanism to prevent it. But that is not the case with carbohydrate. The dog has very sophisticated, sensitive and efficient mechanisms for breaking down carbohydrate and ensuring its absorption. We can be sure that the dog has evolved as a species capable of utilising carbohydrate.
But, says Dr Billinghurst, carbohydrate causes so many health problems e.g. inflammatory disease e.g. pancreatitis. That conflicts with the evolutionary argument (a species would not adapt mechanisms to subsist on a food which was harmful). My experience is that I have had excellent results in treating and preventing inflammatory disease using both home cooked and Burns diets which are based on whole grains i.e. high in carbohydrate. That doesn't mean that all cereal based foods are desirable. Carbohydrate comes in numerous types and qualities. Many commercial pet foods are based on cereal bi-products of other industries. Refined carbohydrates especially simple sugars which are liable to cause problems, not complex unrefined grains.
Let's look at the example of pancreatitis which in the dog is usually an acute disease -either one-off or recurring attacks. The exact cause, if there is a single cause, is not clear but current thinking is that attacks of pancreatitis are associated with high circulating fat in the blood, and are more likely in the overweight dog. Prevention of recurrence is best achieved by sticking to a low-fat diet. No mention of carbohydrate there although of course obesity will occur if the calorie intake is excessive whether from excess protein, fat or carbohydrate.
In his book, Dr Billinghurst mentions pancreatitis as a possible hazard when starting the Barf Diet. He says that this is more likely in the overweight dog receiving too much fat from, for example, fatty lamb. He himself recognises that fat causes pancreatitis and I must assume that he has encountered this condition several times on the BARF Diet.
In my experience there is no danger of that happening to a dog changing to a diet high in complex carbohydrate like brown rice or whole oats.
There are many examples of disease conditions which can be treated and prevented long-term by feeding complex carbohydrate. On a simple level what vet has not recommended chicken and rice to treat gastro-intestinal disease? In his own book, Dr Billinghurst recommends using the water from boiled rice to treat diarrhoea caused by introducing the BARF Diet.
Dr Billinghurst says that raw vegetables must be ground up before feeding. Should the vegetables not be fed raw as they would be eaten in the wild?
Dr Billinghurst says that raw vegetables are indigestible and that grinding mimics the churning action of the stomach and intestines of the dog's prey.
I suggest that grinding raw vegetables mimics the chewing by the herbivore.
Consider what happens to the contents of the digestive tract of the herbivore:
This would contain all manner of herbaceous material including grains.
This is churned and digested by bacteria and digestive enzymes at a temperature of say, 101 degrees Fahrenheit for a period of several hours. Is that not a cooking process? If one wanted to mimic the stomach contents of the herbivore would it not make more sense to feed cooked vegetables and grains rather than raw?
Why does the BARF Diet not advocate feeding actual rumen contents? You can be sure these would be freely available from any abattoir which would be glad to find an outlet for the surplus.
The Cooking Question
Dr Billinghurst tells us that there are enzymes in raw food and these help to digest the food. Cooking kills these enzymes and this reduces digestibility compared to raw.
I have spoken to a veterinary molecular scientist about the existence of these enzymes. I have searched the literature. I am none the wiser. A colleague has enquired of Dr Billinghurst who said that there are millions, too many to name.
Simple common sense and experience tell us that cooking actually increases digestibility.
We know from traditional Oriental medicine that if a person has a digestive disorder their food should be cooked for a much longer time in order to make it more digestible. The amount of faeces produced on Burns food is very small. This shows a very high degree of digestibility.
Increasing the digestibility of the food is an important way of treating bowel disease and problems of malabsorption and cooking does this.
Cooking destroys nutrients
This is true for certain nutrients e.g. Vitamin C and perhaps some Vitamin B. A healthy dog makes its own Vitamin C, and B vitamins are produced by the gut micro-organisms. A pet food high in whole, unrefined cereals contains enough Vitamin B before cooking to ensure that sufficient remains to meet the animal's needs after the cooking process.
Cooking fats produces harmful free radicals.
Free radicals are molecules which cause cell damage. They are produced by normal cellular metabolism and by exercise. Anti-oxidants in the diet or produced by the body itself neutralise free radicals. Good health depends in part in maintaining a balance between the production and neutralisation of free radicals.
In the healthy animal, the amount of free radicals produced from normal metabolism is low and so is the need for anti-oxidants. In case of inflammation however, a great number of free radicals are produced and this is when there is a greater need for anti-oxidants.
A good-quality diet which prevents inflammation and builds natural immunity ensures an adequate supply of anti-oxidants.
Dr Billinghurst's argument invites the conclusion that cooking is detrimental to the health of humans as well as to animals. Is he advocating that humans should eat only raw food?
The BARF philosophy, while claiming to be founded on the principles of evolution is actually an attempt to refute the most basic principle of evolution, - that species adapt to a changing environment, including variation in the food supply.
If the BARF arguments are wrong, does this mean that feeding raw food is also wrong?
I agree with Dr Billinghurst that nutrition is the most important factor influencing health and I agree that the majority of the illness we see in pets is related to feeding commercial pet foods. I have no doubt that the type and quality of ingredients e.g. soya, cereal and animal bi-products, wheat, chemical adulterants which go into most commercial foods are largely responsible for this.
I am sure that the BARF Diet is effective for many pets and their owners but my own experience confounds Dr Billinghurst's claim that his is the only correct way.
Because of the diversity of the dog population there will undoubtedly be some dogs who will do better on a raw/BARF diet than on a cooked diet. But the opposite is equally true.
My experience over a number of years of recommending a diet based on unrefined cereals, vegetables and meats, whether cooked at home or commercially prepared, is that this acts holistically to provide health benefits equal to those claimed for the BARF diet.
My main criticism of the BARF philosophy is its self-righteousness. BARFism argues with a certainty which bears comparison to religious fundamentalism; it brooks no dissent. It advocates a system which is impractical and does not fit well into the lifestyle of present society, denying the possibility of alternatives, thereby condemning those pet owners, the majority, to feelings of inadequacy for failure to follow its teachings.
I said earlier that Dr Billinghurst gave a paper to the American Veterinary Holistic Society. His paper was called "Evolutionary Nutrition for Pets – Hearsay and Dangerous, or Hard Science and Healthy? I will leave you to make up your own mind on the answer to that question.
Is it not also unfortunate that those of us whose main interest is in improving pet health through proper nutrition should be criticising each other rather than the real culprits – the producers of the poor quality pet foods which do cause the problems?
By John Burns BVMS MRCVS
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