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Keto versus Vegan diets

Keto versus Vegan diets

On the matter of the keto vs vegan debate, this blog will try to keep it simple and keep to the basics. Which diet is superior from the point of view of health, fitness and longevity?

Traditionally, the keto vs vegan debate is an area that arouses strong emotions. In this blog post, I am going to seek to avoid ethical and moral questions (a subject for another blog at another time) and focus on health. By doing this, I hope to be able to reach a strong and clear conclusion, and not allow the analysis to become bogged down in nebulous and complex matters of morals and ethics.

What is the Keto Diet?

I go into this question in other blogs here and here. In the simplest terms, the ketogenic diet is a low carbohydrate, high-fat diet. You sometimes see this shortened to LCHF. There are other forms of low carbohydrate diet, but keto specifically advocates the consumption of fat in place of carbs. It is a very effective diet if you wish to lose weight. This is not by any means the only benefit though. It is also a very effective diet for addressing a wide range of challenges to our health.

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The point of using fat as the most source of calories in the diet, rather than carbohydrate, is to promote ketosis. Ketosis is a bodily process whereby the body will burn through its own fat stores in the absence of glucose. Glucose is produced in the body through the intake of carbs. In ketosis, your fat stores become the main source of energy via ketones. Switching over to ketones, rather than glucose, as the main source of energy comes with a range of advantages.

Other benefits of a long term ketogenic diet are its favourable effects on heart disease, cancer, Alzheimer’s disease and on the immune system, to name but a few.

What is the Vegan Diet?

A vegan diet attempts to obtain all the necessary nutrients a body needs only from plant sources. The diet prohibits the consumption of animals, fish and dairy food sources. Veganism takes an ethical position on food, the idea that consumption of other creatures or their products is morally wrong.

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Seventh Day Adventists

Much of the modern impetus for veganism and vegetarianism came via the Seventh Day Adventist Church. Many of their members were highly influential on dietary trends at the turn of the 20th century (John Harvey Kellogg, of Cornflakes fame, is perhaps the most famous example). That influence remains in place to this day. One of their core beliefs was that the consumption of meat lead to the increased expression of lust.

In this day and age, we understand that having a healthy sex drive is a sign of vitality, but for the Seventh Day Adventists, this was mired in sin. All this is highly peculiar, mainly because it is. For now, I will merely note the influence of such people for fear of being sidetracked, although I do plan to go into it in greater depth in a future blog.

Political Influences

In the modern world, veganism has been caught up with other social and political movements. Perhaps the most obvious of these is the environment and global warming. Most of the thinking is rather woolly though, and doesn’t really stand up to serious scientific investigation (here is one example among many)

Main Benefits of a Keto Diet?

I have spoken of these in many of my previous blogs, and will no doubt do the same in the future. I would urge the reader to check these out for themselves. They are very relevant in the keto vs vegan debate. For now, though, I think I will simply list some of the most profound benefits.

  • Weight loss. The keto diet is a method par excellence if you wish to lower your weight.
  • Great Improvement in Insulin Sensitivity – keto has an enormous impact in this area and is part of the reason why the diet helps defend us from the dangers of type 2 diabetes.
  • Improvements in HDL Cholesterol levels – High Density Lipids (the ‘good’ cholesterol) are often increased on a ketogenic diet.
  • Improvements in Blood Pressure Control – Numerous studies have indicated that a keto diet can help to decrease blood pressure readings, especially in people suffering from type 2 diabetes or who are overwieght.
  • Positive effect on mood – without the insulin spikes created by high carbohydrate diets, a person’s mood on keto tends to be calmer and more moderate.
  • Day long energy – again, although a person on a keto diet may not experience the sudden surges of energy following an insulin spike, they don’t experience the subsequent depletion of energy either. Being in ketosis tends to be experienced as having access to steady, long term energy.
  • A measure of protection against a range of diseases – these included such major challenges as cancer, Alzheimer’s, type 2 diabetes, and a range of psychological ills and many more. As ever, consult your doctor or medical professional for more information.
  • Improves Acne and other skin conditions – There is much evidence that a ketogenic diet can favourably affect skin conditions such as acne. This is something I can personally attest. Before adopting a ketogenic diet in mid-2020, I had suffered long term from an acne-like condition on the forehead. My doctors had prescribed a wide range of medicaments over the course of about ten years. None of these had any effect whatsoever. After one month on keto, the rash had gone and has never returned.
  • Anti-inflammatory properties – this was my original reason for adopting the diet. The keto diet works on inflammation via a range of pathways, including the promotion of beta-hydroxybutyrate. This is one of the main ketones. One of its properties is that it an act to block immune system receptors linked to inflammation.
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This is by no means an exhaustive list. Suffice it to say that the benefits of a ketogenic diet are both far reaching and profound.

Main Benefits of a Vegan Diet

At this stage of the keto vs vegan debate we need to examine the pluses of a vegan diet. Before embarking such a list though, I feel I have to admit to an anti vegan bias. I was vegetarian/vegan for several decades before I adopted a ketogenic diet for health reasons, hence I am disproportionately aware of the limitations of a vegan diet. This, perhaps, should be borne in mind when reading the following.

  • A vegan diet can help you to lose weight – a well constructed, wholefood, vegan diet can help to shed weight.
  • A vegan diet, properly constituted, can help to lower insulin levels.
  • There is a belief that a vegan diet can help protect against certain types of cancers, most notably colorectal cancer. As ever with vegan diets, the evidence comes from epidemiological studies, a much poorer standard of proof than randomized controlled trials.
  • Another common claim for vegan diets is that they are associated with lower levels of heart disease – again here, the keyword is ‘associated’. This basically means that the evidence, yet again, comes from epidemiological studies.
  • Vegan diets are associated with lower blood pressure readings – more of the same, I’m afraid. It may well be that vegan diets do, in point of fact, help to lower blood pressure. The problem is that the evidence to support such an assumption seems to be mostly observational once more.
  • More committed vegans tend towards wholesome, non manufactured produce – this is something that they share with the more committed followers of a ketogenic diet. Whichever choice of diet one makes, I think it is clear that the avoidance of the sort of mass-produced, sugar enhanced, vegetable oil-soaked junk food that fills our supermarkets is always a wise move.
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A small disclaimer here. As I researched and wrote the above, I was somewhat amazed at the poor quality of the evidence to support the notion that a strictly vegan diet is healthy. I had heard, and read, that much of the evidence was merely observational or epidemiological in nature, but I had no idea just how all-pervading this was. I find it quite disturbing, especially considering how often veganism is currently promoted on health grounds, that the support for such claims is so thin.

Problems of a Keto Diet

There are, of course, problems with the keto diet, and these should be mentioned in any reasonably objective keto vs vegan debate. It definitely does not suit everyone. To do it properly, it requires a certain degree of discipline that not everyone is capable of. The range of food choices is much diminished in comparison with a ‘normal’ omnivore diet, even perhaps with a vegan diet. I can attest to many a visit to a store only to find absolutely nothing worthy of consumption.

Healthwise, too, there are some who should be cautious embarking on a ketogenic diet. Because of the high fat, high cholesterol content, some feel that those with a history of heart problems should avoid keto. I personally do not subscribe to this view, but I can understand those who are somewhat concerned. Those with thyroid problems may also wish to go into the available studies before committing to keto. It can lead to a reduction in active thyroid hormone ( T3), although other aspects of the diet appear to mitigate this effect.

On a less serious level, temporary inconveniences (…) such as constipation can be a very uncomfortable aspect of the diet. This is something I have first-hand knowledge of. Care must be taken to remain hydrated and keep up the intake of sodium and other essential salts.

Bad breath is another oft-reported problem. This is because of the presence of acetone, a ketone body. My own breath smelt like nail varnish originally, much to the annoyance of the wife, but the effect does seem to diminish over time.

The keto flu should also not be forgotten. Although temporary, the effects usually lasting only one or two weeks, it is pretty unpleasant to go through. It is manageable though, as this previous blog attests. Unfortunately, many folks starting out keto give up at this early stage before reaping the rewards of their efforts.

Problems of a Vegan Diet

These are fairly numerous. So numerous, I think, that a list is again called for.

  • Vitamin B12 – A deficiency in this vitamin may show up in a range of symptoms: weakness, fatigue, poor coordination and balance, mouth ulcers and glossitis (sore tongue), shortness of breath, dizziness, mood changes, etc. The vitamin is easily accessible in animal sources but more or less completely lacking outside of those.
  • B vitamins in general – The other seven B vitamins (B1 through 7 and 9) also tend to be somewhat lacking in vegan style diets These are all readily available through animal-based sources.
  • Vitamin A – This deficiency tends to manifest itself in eye problems and weak immune systems. This vitamin is readily available in meat, dairy, fish and eggs.
  • Calcium – This deficiency has negative implications for bone health. Calcium is particularly needed in periods of growth, hence the dangers of adopting a vegan diet at too young an age. Lack of calcium can lead to osteoporosis. This can lead to increased skeletal weakness and a risk of broken bones.
  • Vitamin D – This comes in two flavours: D2 and D3. D2 is found in plants but is much less efficiently absorbed than D3. The latter is found in animal-based foods, particularly egg yolks and fatty fish.
  • Iron – Anaemia (iron deficiency) is a commonly encountered problem on a vegan diet. There are plant sources of iron, but often care has to be taken to ensure that the vegan dieter is getting a sufficient supply. Iron is plentiful in meat, particularly liver, in an easily bio-available form.
  • DHA and EPA – are essential omega 3 fatty acids. They are vital for healthy brain development, therefore particular care is indicated in relation to children on restrictive diets. ALA (Alpha Linolenic Acid) is a form of omega 3 that can be obtained via plants, but it is very poorly utilised in the body in comparison with animal sources. These come in the form of DHA (DocosaHexaenoic Acid) and EPA (EicosaPentaenoic Acid).
  • Zinc – This mineral is vital for healthy immune systems, metabolic functions and cell repair. When tested, zinc deficiency is very common amongst vegans. Although zinc can be sourced from plants, it is often poorly absorbed because of the presence of their phytate content.
  • Iodine – This is another shortage common on vegan diets. It is not made in the body, therefore we need to get it in our diets. It is used to produce thyroid hormones that have an essential role to play in metabolism and growth. Adequate sources are readily available in fish and dairy products, but far more difficult to come by on a strict vegan diet.
  • Choline – This is essential for brain development. Pregnant women and breastfeeding mothers should take particular care here. Good sources are meat, dairy and fish. To be fair, there are plant sources of choline, but as ever on a vegan diet, care must be taken to ensure that sufficient amounts are accessed.
  • Protein – Unlike most plant-based sources of protein, animal proteins are complete. A complete protein is one that contains all nine amino acids. For the most part, vegans have to combine protein sources to make the desired complete proteins. There are a few plant sources such as quinoa, buckwheat, hempseed and soybeans, but these contain nowhere near the amounts of animal-based sources.
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This list is by no means exhaustive. I feel it is sufficiently long, however, to demonstrate just how easily a vegan diet can lead to deficiencies in a range of vital nutrients. Many ex-vegans subsequently bear witness to this. It is clearly possible to adopt a vegan lifestyle long term, but to do so you need to be very aware of a huge range of potential threats. To cover this, many vegetarians spend their mornings having to take a whole range of pills, potions and supplements. This in itself should be clue enough to how ‘healthy’ the diet actually is.


In conclusion, from a relatively objective point of view (though I cannot myself really claim complete objectivity in this matter), there is only one possible winner in the keto vs vegan debate. Keto, despite its challenges and the amount of discipline required to stick with it, wins the contest hands down.

In this analysis, I have approached the question mostly from the point of view of health. The question I have addressed is which of the two diets in the keto vs vegan debate is the healthier. If we restrict the debate to health and nutrition then the answer is clear. On the other hand, there is a complex and multi-faceted debate to be had on moral and ethical grounds. I feel though that such a debate would render this particular post far too complex. Whilst one can come to relatively clear conclusions in matters of nutrition and science, ethical and moral questions are far more difficult to answer.

Each of us has to live with the consequences of our decisions, be they good or ill. We all have to decide where our primary responsibilities lay. I am not at all sure it is a wise choice to believe that you are saving the planet whilst your own health is being compromised. One’s primary responsibilities are to oneself, one’s family and one’s community. Often when we reach beyond this we take on questions we can have little or no influence on.


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