Is The Keto Diet Dangerous?

Is the keto diet dangerous? Before we answer that, it’s important to note that the rise in popularity of the keto diet did not just appear out of nowhere. It appeared against a background of rising diabetes, obesity, chronic health issues and an increasing number of people who reported having no energy and feeling tired all the time.

The traditional dietary advice of “fat is bad for you”, eat low-fat, eat cereals and lots of fruit and vegetables wasn’t working. Diabetes cases increased, the rate of obesity doubled and it’s clear to anyone who cares to look that what we use to consider a healthy diet is anything but.

The fact is, thousands of people have succeeded with keto where all other diets failed.

But there some who believe the ketogenic diet is dangerous so let’s take a closer look to see if they’re right.



When you start looking into whether the keto diet is safe, you will likely come across a study that cited children with epilepsy being treated back in the 1920s with a therapeutic ketogenic diet. That is, this version of the keto diet was prescribed as a medical treatment, not as a comprehensive diet plan. These children did indeed suffer being on such a diet – they had osteoporosis, stunted growth curves, kidney stones. Critics of the keto diet often refer to this as evidence that the keto diet is dangerous.

Yet, what is conveniently ignored is that the diet these children were on was not the keto diet we know today. Those children were not eating ribeye steaks, salmon and broccoli. These children were not eating a nutritious, whole-food ketogenic diet. They were literally being force-fed industrial liquid seed oils such as cotton-seed oil, corn oil, soy-bean oil. That is clearly not the keto diet we are talking about these days.

(And while force-feeding oil to children sounds cruel, it needs to be taken into context. This was 100 years ago and scientific medicine was not as advanced. These children were suffering from unrelenting seizures and whilst this diet was not particularly healthy, it seemed to work. It was healthier to give children this oil-based diet than them having seizures every day for hours at a time until they died an early death.)

So, the keto diet we’re talking about is definitely not advocating drinking large amounts of oil.


Prebiotic fiber – also known as soluble fiber – is the non-digestible part of foods like bananas, onions and garlic, artichoke, the skin of apples, chicory root, beans, and many others. Prebiotic fiber goes through the small intestine undigested and is fermented when it reaches the large colon.

This fermentation process feeds beneficial bacteria colonies and helps to increase the number of desirable bacteria in our digestive systems that are associated with better health and reduced disease risk.

Prebiotic fiber is vital for a healthy gut microbiome and critics say keto is dangerous because it lacks this fiber.

Before we answer this, what is the gut microbiome? The gut microbiome is a vast ecosystem of organisms such as bacteria, yeasts, fungi, viruses and protozoans that live in your digestive system. Collectively, these micro-organisms collectively weigh up to 2kg (heavier than the average brain)!

The gut microbiome is increasingly treated by scientists as an organ in its own right and research suggests it plays several roles vital for good health:

  • the digestion of food
  • the immune system
  • the central nervous system
  • controlling bloody sugar levels
  • may affect brain health and mood. Studies suggest there is a link between the health of the gut microbiome and depression.

The gut microbiome is an incredible thing – but research into it is relatively new. There is still a lot we don’t know about how it works – which bacteria is good, which to eliminate, how all the microbes interact with each other in this incredibly complex biological ecosystem.

So, we need to be careful when people make sweeping statements that keto is dangerous because it lacks prebiotic fiber because (1) that’s not true, and (2) we don’t truly know what fiber and what foods are good for the gut microbiome. Yes, we have a fair idea but no one knows for sure. No one – not even the scientists working in the field – can yet categorically state which foods to eat, which to avoid and which diet is best for our gut microbiome.

We simply don’t know at this time what the optimal gut bacteria ratios and such are. Hopefully, one day we will know but for now, no one has the answer. (Indeed, the gut microbiome scientists study today may be the result of living on an unhealthy high-carb, high-sugar diet for much of our life and may not be the best gut microbiome to model).

Secondly, to say the keto diet is low on prebiotic fiber is just not true. Sources of keto soluble fiber include: avocado, flaxseed, pumpkin seeds, leeks, broccoli, cauliflower, sprouts, cabbage, turnips, kale, bok choy, chia seeds, radishes… It’s just not true to say keto lacks fiber.

And while you don’t want to eat too much of these because they still have a carb content, it’s fine to eat chia seeds, flaxseed and asparagus without worrying too much.

It’s also interesting to note that many people who say keto is bad for you has – surprise, surprise – a supplement to sell you. You don’t need any supplements on keto and all the keto pills, powders and potions are snake oil.


Some people believe the keto diet is stressful. They say it’s stressful to follow; stressful to get into and maintain ketosis and are not sure whether keto is sustainable.

Many things in life are potentially stressful but it’s about the types of stress and the context of that stress. Yes, there’s bad stress (losing your job, being ill etc.) but there’s also good stress – stress that makes you grow (learning a new skill, intense exercise). If the ketogenic diet is stressful at all (and we don’t know if it is), then it’s a good form of stress. It’s your body reacting to change that is going to make you better, healthier and happier.


Some critics of the keto diet say it will give you fatty liver.

Fatty liver happens when fat builds up in your liver. Having small amounts of fat in your liver is normal, but too much can become a health problem.

Too much fat in your liver can cause liver inflammation, which can damage your liver and create scarring. In severe cases, this scarring can lead to liver failure.

What causes fatty liver?

  • Obesity
  • Excessive alcohol consumption
  • High blood sugar
  • Insulin resistance
  • High levels of fat, especially triglycerides, in your blood

Look at that – the very things that cause fatty liver are the things the keto diet eliminates! In fact, keto does not cause fatty liver – it can actually reverse it. (We think the term “fatty liver” is potentially misleading – it should really be known as “sugary liver”!)

Even the last point – high levels of fat in your blood – is not an issue. When you’re in ketosis, your body is burning fat for fuel 24/7. The fat isn’t just swimming around in your blood clogging everything up – it’s being used at a rapid rate – by every process and every organ in your body. And the keto diet has been show to significantly reduce triglycerides (bad fats) levels.


Atrial fibrillation is a heart condition that causes an irregular and often abnormally fast heart rate.

A normal heart rate should be regular and between 60 and 100 beats a minute when you’re resting. In atrial fibrillation, the heart rate is irregular and can sometimes be very fast. In some cases, it can be considerably higher than 100 beats a minute.

This can cause problems including dizziness, shortness of breath and tiredness.

You may be aware of noticeable heart palpitations, where your heart feels like it’s pounding, fluttering or beating irregularly, often for a few seconds or, in some cases, a few minutes.

Atrial fibrillation is not usually life threatening, but it can be uncomfortable and often requires treatment – and if you experience it, you should make an appointment to see your doctor.

The idea that a low-carb diet can cause atrial fibrillation is, in our opinion, unfounded. The original study that came to this conclusion looked at participants whose daily diets comprised 48.8% carbohydrates! That’s not a keto diet. Heck, that’s not even a low-carb diet!

A true low-carb, whole-food, real-food ketogenic way of eating will lower your risk of many heart diseases which are often contributory factors in atrial fibrillation.


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