One of the most popular subjects for discussion and debate in pet health for many years now has been the relative merits of commercial pet foods and unconventional diets of various types, including homemade cooked and raw diets, commercial raw diets, vegetarian diets, etc. Some pet owners and veterinarians have concerns about the safety and health effects of commercial diets, though only some of these concerns have any real evidence to support them, and most of the negative claims about commercial pet food are unsupported or simply inaccurate.
Most veterinarians are more concerned about the safety and nutritional adequacy of unconventional diets. Homemade cooked diets have been repeatedly shown to be unbalanced and nutritionally incomplete if not formulated by veterinary nutrition specialists. Diets incorporating raw meat, both commercial and homemade, present a serious risk of food-borne infectious disease to pets and humans (1, 2, 3, 4, 5, 6). Vegetarian diets may be adequate for dogs if carefully formulated, but they are likely unsafe for cats, and there are no demonstrated benefits for either species.
Subjectively, there seems to have been an increase in pet owners’ interest in and use of unconventional diets n the two decades I have been in practice. While most do still feed at least some commercial cooked foods, many are experimenting with homemade or raw diets despite the risks and lack of evidence for any benefits. A new study has tried to assess how popular such diets really are and how this has changed over time.
Dodd, S., Cave, N., Abood, S., Shoveller, A., Adolphe, J., Verbrugghe, A.
(2020) An observational study of pet feeding practices and how these have changed between 2008 and 2018 Veterinary Record Published Online First: 18 June 2020. doi:10.1136/vr.105828
The authors began by reviewing the literature for previous studies that investigated pet owners’ feeding practices. They then conducted an online survey asking pet owners about their use of conventional, homemade, and raw diets. The results suggest that while most people still use conventional and cooked diets, the inclusion of raw and unconventional diets is increasing. There also appear to be some regional differences in feeding practices. The table below summarizes the comparison of the current study with past reports.
Overall, the results suggest that most pet owners feed some conventional commercial food to their pets. However, it also appears that a higher percentage of owners include homemade cooked or raw foods as some or all of the diet for their animals. Well over half of the respondents indicated they feed at least some raw animal products, and in some locations (e.g. Australia) this appears to be even more common.
There are, of course, significant limitations to this study. The data was collected by an online survey shared on social media. This obviously represents a subset of the pet owning population, and it is particularly easy for passionate advocates of one extreme or uncommon type of diet or another to promote the survey and create the false impression that their views are more widespread or popular than they really are. Advocates of unconventional diets or medical approaches always seek to gain legitimacy by exaggerating the popularity of their views (despite the fact that popularity isn’t a measure of truth or scientific merit anyway).
However, it is worth considering that this study might reflect at least some real growth in the popularity of unconventional diets, including raw foods. This possibility has to be taken seriously given that such diets, and the unscientific reasoning or distrust of mainstream scientific evidence and opinion that often lies behind them, represent a real threat to animal health. In the absence of any reliable evidence for health benefits from such diets, the risks are clearly not worth taking, and any evidence that this message is not being heard or understood by pet owners should motivate veterinarians and proponents of science-based nutrition to work harder at educating the public about the risks and benefits of various feeding options.
Interesting article, thank you.
I know the big brand foods have been tested over and over, so therefore should be the gold standard. And also I know that many dogs are being fed raw diets that are woefully unbalanced. But what about raw meals formulated by a university trained canine nutritionist? Is there are place for them in a dog’s diet?
From a nutritional standpoint, it is likely that a raw diet can be complete and balanced if properly formulated (though I will say even that isn’t certain in light of the study run by nutritionists at UC Davis which involved feeding raw rabbit to cats and which led to severe heart disease in some of the subject). However, even if complete and balanced, the risk of infectious and parasitic disease will be the same, and there is still no reason to think it would have health benefits.
Thanks for your reply. A whole rabbit is by no means balanced and complete, and is low in taurine and/or its precursors, so the study is not really relevant. I understand that Big Pet Food has the dollars to spend on studies and marketing, and can influence a huge section of the market, while the nutritionists and brands promoting balanced raw & cooked foods have no such resources, as yet. But surely as more pet feeders wish to explore “healthier” options this will change. I understand that the studies show that everything a dog needs is in Big Pet Foods’ formulations, but I find it incredibly hard to understand why, when humans are being urged to eat less processed food and more fresh food; and free range, grass fed animal products are becoming more popular, the pet food and pet healthcare industries consider this anathema. And not only promote highly processed foods, but foods containing predominantly grains. I’m curious to know why there’s such resistance, why the science has halted at this point?
Go back in time to when Ignaz Semmelweis was scorned, and lost his job, for promoting hand washing as a disease preventative. Alfred Wegener was ridiculed & ostracised for postulating plate tectonics. When baby formula manufacturers actively promoted against breastfeeding, and deliberately ignored oligosaccharides in breast milk, because “they had no purpose” and scientists knew better. It’s my fervent hope that pet food science will one day focus on fresh foods, and we’ll be able to feed our dogs something more species appropriate than meat flavoured grain.
You missed my point. My point is that a group of nutritionists at a university felt it would be an appropriate diet and were surprised when it wasn’t, so the general idea that a raw diet formulated by nutritionists would be safer than one not so formulated is not accurate.
When you start using labels like “Big Pet Food” your bias is showing. Companies that make raw diets are in it for the money just like conventional companies, and they have the same responsibility to prove their product claims. It’s a cop-out to claim they don’t have the resources, and it’s irrelevant since they shouldn’t be making claims they don’t have data to prove. If there is any real evidence that raw diets have health benefits, the big companies will jump on the bandwagon and take over the market just like they did with grain-free diets, so the idea that these companies are somehow against raw feeding is not how the market works.
1. “processed foods” in human nutrition means snack and convenience foods designed for taste and commercial appear with no concern for nutrition. This is not the same as commercial pets foods designed to be supportive of good health. The fact that both are commercially produced does not make them equivalent.
2. Free-range and grass-fed meat have nothing to do with health (neither, for that matter does the even more popular organic designation). There might be ethical reasons to prefer eating animals raised in this way (I don’t eat meat at all, primarily due to ethical concerns), but there is no reason to think these have health benefits.
3. The idea that grains are inherently unhealthy, for humans and animals, is a fad, not a legitimate health concern, so it is not an example of something we should extrapolate from humans to pets.
4. Science hasn’t “halted.” Advocates of novel feeding approaches should do the research and prove their claims, like everyone else. There is no responsibility for others to either test these claims for them or accept them without evidence. Some research is being done on raw diets, and so far it hasn’t produced convincing evidence of benefits, but if there are benefits then it is up to those advocating such diets to make their case.
Irrelevant. Some people whose ideas were dismissed turned out to be right. many, many more turned out to be wrong and were forgotten. If you have a good hypothesis with plausible mechanisms and specific, testable ideas, you will find academics, private groups (e.g. Morris Animal Foundation), and companies looking to make money who will invest in testing it. Nobody is preventing this from happening, but those of us who do not find the hypothesis convincing aren’t going to do the work for you.
You’re right, and I do tend to let hopes, dreams & emotions get in the way of critical thinking. I have Linda Case’s food logic book on my wish list. I had better prioritise it. Thanks for the good points, and yet more food for thought.
Its a really good book. I hope you like it. Thanks for the discussion!
I am embarrassed to admit that I once believed in the raw pet food fad. I believed in internet strangers with no credentials and no sources and believed that vets were not sufficiently educated in animal nutrition. I began feeding my cat raw chicken as a treat and he eventually started having really bad diarrhea. I had fed some raw on and off for years and had never had any other issues. First, I went to my beloved internet forum and asked for some advice. You know what they did? They deleted my question because I didn’t feed fully raw. When my cat started squatting without producing anything, that’s when I took him to the emergency vet. The vet gave me medicine that helped and told me not to feed raw chicken anymore.
Years later, I took in my senior cat to be seen regarding her constant vomiting. Guess what helped? A therapeutic commercial diet.
Looking back, I feel like a dummy. It’s like being a flat earther or an anti vaxxer. I love my cats. I have a bachelors degree. And I still got suckered in. I am much more careful now about looking for sources and following the science. That’s how I got here! I just wanted to add in another perspective. Anyways, thanks for the educational and easy to read blog!
Glad you found the blog useful. I wouldn’t feel bad about feeding raw in the past. The arguments for it sound pretty reasonable at first, and plenty of vets have fallen for them!
I’m as skeptical about what seem to be fad-driven trends as anyone, but nevertheless must quibble with one of your comments:
> Free-range and grass-fed meat have nothing to do with health
This is most likely true in the case of “free-range,” but incorrect regarding grass-fed:
“Research spanning three decades suggests that grass-based diets can significantly improve the fatty acid (FA) composition and antioxidant content of beef, albeit with variable impacts on overall palatability. Grass-based diets have been shown to enhance total conjugated linoleic acid (CLA) (C18:2) isomers, trans vaccenic acid (TVA) (C18:1 t11), a precursor to CLA, and omega-3 (n-3) FAs on a g/g fat basis. While the overall concentration of total SFAs is not different between feeding regimens, grass-finished beef tends toward a higher proportion of cholesterol neutral stearic FA (C18:0), and less cholesterol-elevating SFAs such as myristic (C14:0) and palmitic (C16:0) FAs. Several studies suggest that grass-based diets elevate precursors for Vitamin A and E, as well as cancer fighting antioxidants such as glutathione (GT) and superoxide dismutase (SOD) activity as compared to grain-fed contemporaries.”
Daley, C.A., Abbott, A., Doyle, P.S. et al. A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef. Nutr J 9, 10 (2010). https://doi.org/10.1186/1475-2891-9-10
These diets may change the profile of fats in the meat, but this does not itself demonstrate any health effects. You would have to show that people or animals eating this kind of meat had different health outcomes than those eating grain-fed meat, and that has been done. The role of various types of fats and antioxidants in health has turned out to be a lot more complicated that originally supposed, and fish-oil supplements or antioxidant vitamins have turned out to a lot less useful than once hoped. The connection between the fundamental biochemistry and real-world health effects is where the rubber meets the road, and there is still no strong evidence that grass-fed meat can change health outcomes.