The Flexitarian Diet: Potentially Sustainable But Morally Questionable

flexitarian diet

A flexitarian is someone who has a primarily vegetarian diet, but who occasionally eats fish and meat. Not all flexitarians are alike. As the name suggests, it is a flexible diet. While one person may only meat at the weekends or one day a week, someone else may reserve meat for dinner only, and another flexitarian might only eat meat and fish when eating out. Paul McCartney has been promoting the flexitarian diet with the concept of Meat Free Mondays.

There are criticisms that flexitarianism is cheating. While a flexitarian can feel confident that they have less of a carbon footprint than a carnivore, a vegetarian or vegan may still contest that the diet still involves the regular consumption of food products that are environmentally damaging. Then there’s also the ethical argument that eating any animal product is wrong because it involves participating in the exploitation and suffering of sentient non-human animals. Comedian Simon Amstell’s first feature-length film Carnage is based around the idea that in the future we will look back on our meat-eating past with disbelief and horror.

But right now, it seems that many people are finding it easier to become a flexitarian than a vegan. There’s also the argument that flexitarianism is a gateway diet, towards not only full vegetarianism but also veganism (which excludes the consumption and use of all animal products). And it’s still true that reducing your meat consumption and increasing your consumption of plant-based foods can make a big difference to one’s environmental impact and health.

In this piece, I will point out why the flexitarian diet is potentially sustainable, in that, if the diet involved a big enough reduction in meat and fish consumption, and if widely adopted, then food production and consumption would have a low environmental impact while preserving natural resources for future generations. But I will further add that, while flexitarianism can reduce suffering, this does not somehow morally justify the continued mistreatment of non-human animals, which is still made possible by a flexitarian diet.

The Problem With the Meat Industry

The world needs more flexitarians because of the immense environmental damage caused by the meat industry. One paper concludes:

Meat sector is one of the leading polluters in the food industry. Regardless of the perspective, environmental impacts of the meat chain influence three dimensions – climate change in respect to global warming potential, acidification potential and eutrophication potential; consumption of natural resources (mainly water and energy) and; polluting the environment with various types of waste and waste water discharge.

A Flexitarian Diet Can Massively Reduce Greenhouse Gas Emissions

According to the UN’s Food and Agricultural Organization (FAO), animal agriculture contributes to 14.5% of greenhouse gas (GHG) emissions, making the industry more environmentally unfriendly than all transport combined. This figure factors in the dairy and egg industries as well, but the real culprit here is meat.

A fascinating study published in Climatic Change analysed the carbon footprints of various diets: high meat-eaters, medium meat-eaters, low meat-eaters, pescatarians, vegetarians, and vegans. Vegans had the lowest carbon footprint associated with their diet. But the difference between vegetarians and vegans was not as nearly as significant as the difference between vegetarians and both medium and high meat-eaters. Moreover, high meat-eaters created about twice as many carbon emissions from their diet compared to low meat-eaters. The difference in emissions between pescatarians and low meat-eaters also highlights that meat is the least sustainable kind of food that exists.

It’s important to know how we can significantly reduce our carbon emissions. Most climate scientists agree that the main cause of the current global warming trend is human activity creating the ‘greenhouse effect’ – when the atmosphere traps heat radiating from Earth toward space.

The effects of global warming should not be taken lightly or ignored. Experts predict that if the current trend of global emissions continues, then the world will be eight degrees warmer by 2100. This will result in more frequent and severe weather, including storms, heatwaves, floods, and droughts. A hotter climate creates an atmosphere that can both retain and release more water. This leads to wet areas becoming wetter and dry areas becoming drier.

There will be higher death rates, too. Indeed, some scientists describe climate change as “the biggest global health threat of the 21st century.” Climate change is most likely to negatively impact elderly people, children, low-income communities and minorities. Air pollution will also worsen, which causes adverse effects on human health.

Global warming is causing land and sea to undergo rapid changes. This threatens the existence of all kinds of wildlife. Indeed, a 2015 study highlights that vertebrate species are disappearing 114 times faster than they should be. In 2020, we found out that a third of global wildlife has disappeared in the last 50 years due to human activity.

The world’s ice sheets are melting quickly, which is leading to rising sea levels. It is estimated that by 2100, the oceans will be one to four feet higher, threatening some of the world’s largest cities, including New York, Los Angeles, Miami, Mumbai, Sydney, and Rio de Janeiro. Another major effect of global warming is the acidification of the oceans. It puts the planet’s marine ecosystems under pressure, and threatens molluscs, crabs, and corals.

Experts say that even if we stopped all of our carbon dioxide emissions tomorrow, we still would not avoid many of these harmful effects. However, by drastically reducing our global emissions, we can avoid a lot of the severe consequences associated with climate change. That’s why reducing meat consumption is essential.

Livestock Use Up Too Many Resources

Another problem with raising livestock for meat is that it uses up an inordinate amount of resources when compared to growing plant crops directly for human consumption. While this applies to meat in general, our consumption of beef is the most unsustainable dietary choice that we make. Researchers have found that raising beef uses 10 times more resources (i.e. land and water) than poultry or pork.

A flexitarian diet could be based on this kind of evidence. If beef is the least environmentally friendly kind of meat, then a flexitarian may rationalise: Okay, I’ll sometimes eat chicken and fish, but never beef. 

The problem is not just that producing meat uses up a lot of resources, it’s also extraordinarily wasteful. From a common-sense point of view, it’s more inefficient to feed plants to livestock and then eat the animals than it is to grow plant crops directly for human consumption. With both arable land and water becoming scarce resources, we need to find evidence-based ways to combat these serious and life-threatening problems.

The Problem With the Fishing Industry 

Not only is eating too many cows problematic but so is our overconsumption of fish. Many marine biologists believe that the single biggest threat to marine ecosystems is overfishing.

According to the UN, over 70% of the world’s fisheries are either ‘fully exploited’, ‘over exploited’ or ‘significantly depleted’. Some species have been fished to the point of extinction, while many others could end up that way. This is highly problematic. In modern ecology, there is something called the ‘cascade effect’ or knock-on effect, when the extinction of one species leads to the extinction of another (or many more). This is because ecosystems are complex webs of interdependence.

Overfishing is putting the global tuna industry at risk. Therefore, a flexitarian may decide to not only limit their consumption of fish in general but to avoid tuna specifically, given that some species are more at risk of extinction than others.

Friends of the Earth, a network of environmental organisations, recommends a flexitarian diet for its environmental and health benefits. But they also point out that it is but one part of a sustainable diet. Alongside eating less meat and fish, a sustainable diet can include wasting less food and sourcing from known suppliers that have good standards.

Why a Flexitarian Diet is Morally Questionable

A flexitarian diet is often touted as a morally better diet than a standard diet, involving the regular consumption of meat and fish. However, if a flexitarian diet is a flexible vegetarian diet and not a flexible vegan diet, then such a diet would still include the regular consumption of dairy and eggs, which, while not as ecologically harmful like meat consumption, still poses a significant moral issue. These are industries that, even when following ‘organic’ and ‘free-range’ practices, cause immense suffering to non-human animals.

I believe it unjustified to view meat as in a separate moral category altogether from the egg and dairy industries, especially when we consider that both of the latter industries are inextricably tied to the slaughter of non-human animals (i.e. male chicks born to egg-laying hens are not suitable for meat production, and obviously cannot lay eggs, so they are killed via maceration or gassing; and when dairy cows are unable to produce milk, they are sent to slaughter, and male calves born to dairy cows will be sent to slaughter to be turned into veal).

In terms of whether a flexitarian diet is morally better than a standard diet, it is true that a flexitarian will reduce suffering through their dietary choices, with fewer numbers of non-human animals having to live in inhumane conditions and be brutally mistreated and slaughtered, but a reduction in aggregate suffering does not somehow morally excuse continued cruelty toward individual non-human animals. It’s not as if the suffering of non-human animals is a pool of suffering and that if this pool is drained of enough suffering, the remaining suffering is justifiable.

Even a utilitarian, who considers aggregates of suffering and well-being in its analysis of actions, may have to admit that a flexitarian diet is not morally justifiable. That is, unless, you attempt to argue that the pleasure of eating meat and fish (i.e. its taste and enjoyment of eating such food with others) outweighs the suffering of the fewer – but still real – non-human animals that one is occasionally eating. I believe a flexitarian diet could be considered preferable but not moral, in that a reduction of suffering is preferable, as it leads to an improved state of affairs, but the animal cruelty that the diet still funds is just as abhorrent as it is in the case of more regular meat consumption.

For instance, there are many actions we regard as abhorrent that we simply don’t allow wiggle room for, even though engaging in these actions may confer some pleasure or benefits to the person committing the action. In the case of slavery, we have taken an abolitionist approach to it (countries that have abolished it, anyway), which is unquestionably justified. The convenience that slave owners enjoyed is not a factor we can even begin to consider as a reason to allow slavery. And in other cases of morally reprehensible acts, we would not think to consider reductions in suffering as acceptable. We do not deal with child abuse, sexual abuse, or rape in terms of reducing harm, such as merely reducing the numbers of each act to a comfortable level; we rightly aim for elimination and prevention.

When it comes to non-human suffering, we see things differently, which according to many animal ethicists, is due to speciesism: our treatment of species as a morally relevant category, when it is, in fact, an arbitrary marker of moral difference. The consumption of animal products and the pleasure we get from it is a cultural norm. However, we cannot use the normality of it as a justification for it (since this would commit the appeal to the majority fallacy, an argument that a slaver owner in 19th century southern America could make), nor is it so easy to leverage taste pleasure as a strong argument (since abusers can take genuine pleasure in their abuse, whether it be from sexual gratification or power, and moreover, we are at a point where the taste of plant-based alternatives to meat approach, match, and even rival the taste of actual meat; so mouth pleasure is also a weak justification).

Meat is also not necessary for a balanced, healthy diet. According to the American Dietetic Association, an appropriately planned vegan diet is can be nutritionally adequate and provide wide-ranging health benefits as well. If one counters this by arguing that minimal planning counts against the vegan diet, then this, again, amounts to an argument positioning convenience as morally weightier than suffering.

Meat-eating may carry the benefits of feeling part of a group (i.e. eating the same food as everyone else), belonging to a specific culture through its cuisine, or immersing yourself in a different culture through its cuisine, but we should question how much moral weight this carries in the face of a life of misery. Would any person seriously go through such suffering but see it as an acceptable deal if he or she knew that another being would get to enjoy a traditional meal as a result?

Each sentient non-human animal, like each human, is an experiencing subject, and its well-being matters to them specifically. The suffering of each non-human animal does not become negligible because a greater amount of suffering has been alleviated. It’s not as if a cow, pig, or chicken, can become aware of the suffering and slaughter spared to other members of its species and suddenly lose its morally relevant interests. As a result, if a flexitarian diet is not adopted as a practical step, with the goal of veganism in mind, then it will inevitably require an adequate justification for the inclusion of meat (not to mention eggs and dairy products).

The flexitarian diet, if planned in a certain way and widely adopted, could make our consumption of food sustainable; that is, if we also take effective steps to tackle climate change, then we can produce and consume food in a way that uses natural resources without damaging the environment. Yet, as we have seen it is not the most eco-friendly diet and it is certainly morally questionable.


  1. James
    January 9, 2021 / 1:14 am

    Regarding speciesism, I do think it is justified but I also believe that only a vegan diet is moral unless a person’s survival somehow depends on eating meat or using an animal product. Usually speciesism is compared to other types of discrimination like sexism and racism, but I don’t really think that’s valid. One common justification among racists for why white people are superior to black people is that white people are smarter, which is false for an average person of each race.

    For something like a dog vs. a person, a dog is factually less intelligent. In a case of saving a human’s life vs. a dog’s, someone against speciesism may still support saving the human because the interests are dissimilar. A human has a longer lifespan than a dog, a human can enjoy life in more ways than a dog, etc. But if these are features of all humans and all dogs, then this just seems to be speciesism without saying outright that it is.

    I think it was Peter Singer who said like interests count alike or something along those lines, but often for pain a human’s interest isn’t the same as most animals. A human can be traumatized by pain and remember it better than many animals. And when this is a feature of all humans (barring something like brain damage), then speciesism does seem to be justified.

    Anyway, I support Shelly Kagan’s hierarchical moral system of animals. Animals do have some moral standing, but people (not just humans but aliens and artificial intelligences) have more.

    • Sam Woolfe
      January 11, 2021 / 11:40 am

      Thanks for the comments, James. I would have to agree with some of your points. However, I think you would be hard-pressed to find an ethical vegan who would commit to their diet so strongly that they would not think it permissible to consume animal products for survival.

      Regarding the comparison of speciesism with racism, the analogy does not lie in the validity of some of the arguments put forward to justify the discrimination (i.e. superior white intelligence is demonstrably false, whereas average human intelligence is superior to average non-human intelligence); the analogy is based on using arbitrary distinctions to discount the interests and well-being of others. Sticking to the example of intelligence, it is true that the average human adult is more intelligent than average adults of non-human animals, but clearly there are cases where the intelligence of some non-human animals is superior to that of some humans (e.g. in newborns, in cases of cognitive disability).

      I think there may be a danger of confusing speciesism with morally relevant distinctions between beings. Speciesism refers to simply discriminating on the basis of species, rather than morally relevant factors (e.g. degrees of sentience, intelligence, and so on). In the same way, we might refer to health systems providing more resources to a young person over a sick and dying older person as ageism, but if this decision is based on morally relevant factors (e.g. years left to be lived, interests, plans, and so on), then this would not be strictly an ageist decision. But if for semantic reasons, you would want to call these kinds of decisions speciesist and ageist, then that’s fine – we would just have to distinguish between moral/justified speciesism/ageism, and immoral/unjustified counterparts.

      Like interests count alike, absolutely, but you’re right as well to say that human pain is often very different from non-human pain. Human trauma is a great example of that difference. I’ve written about this topic before, with a slightly different conclusion (at least, some philosophers argue non-human animals may experience pain more intensely than humans, for various reasons):

      I would also support Kagan’s hierarchical moral system of animals as a rule-of-thumb, but I think the moral standing that sentient non-human animals have in that hierarchy still means it is not justified to cause unnecessary harm to them. I would probably add to this hierarchy something like Tom Regan’s or Alasdair Cochrane’s conception of animal rights in support of veganism.

      • James
        January 11, 2021 / 2:22 pm

        Since morally relevant factors of degrees of sentience and lifespan are often intimately tied with what species an organism is, I think it does make more sense to call it justified speciesism. Cases such as cognitive defects are aberrations from the norm. Although when dealing with people who put weigh in favor of humans, distinguishing between justified and unjustified speciesism would probably lead to confusion and not be worth the time.

        Kagan’s hierarchy does give animals lesser standing, but it still gives them enough standing to protect them from harm. David Pearce’s analogy with certain nonhuman animals like pigs as comparable to newborns or children is useful, although not exactly the same since Kagan distinguishes between newborns who’ll later gain much greater intelligence vs. an animal that’ll never go beyond a set subhuman level.

        On an interesting note, Pearce thinks his analogy of protecting animals like protecting infants leads to his abolitionist project to eliminate suffering in all sentient life. I admire the project, assuming it could still preserve ecosystems and species, but I do wonder how many vegans would agree with it.

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