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Keto Diet Basics

Is Keto Safe? An In-Depth Look

Published on: June 19, 2018

Is Keto Safe? An In-Depth Look

We all know the positives of going keto: quick weight loss, greater energy, and increased mental sharpness. But what about the downsides and long-term safety?

Unfortunately, the negative side of going low-carb is less talked about. Nonetheless, knowing what can go wrong on keto is just as important as knowing what benefits you can expect.

In this article, we take an in-depth look at those less talked-about aspects of keto. We answer "is keto safe?" and explain what science has to say about this. We also talk about the downsides of going keto and who should avoid this diet.

About the Ketogenic Diet

The ketogenic diet is a very low-carb diet. Carbs on this diet are limited to a meager 50 grams per day, making up only 5-10% of your daily calories. In comparison, dietary guidelines recommend eating around 300 grams of carbs per day, which is 45-65% of your daily calories [1]. In other words, keto turns everything you know about healthy eating upside down.

The goal of going so low on carbs is ketosis, a metabolic state where the body burns fat to make fuel in the form of ketones. Ketosis happens during fasting, starvation, and carb restriction and is a response to low blood sugar levels. When you're in ketosis, your body has made the shift from being a sugar burner to a fat burner.

But despite being a fat-burning diet, keto was not originally designed for weight loss. Researchers in the 1920s developed this diet to treat epilepsy [2]. However, its use as an epilepsy treatment fell back after the introduction of antiepileptic drugs. But recently, the diet went through a resurgence within weight-loss communities.

Is Keto Safe?

Keto is radical. There's no doubt about that. That's the main reason medical experts are raising concerns about the diet's safety. Other reasons are the widely-held beliefs that the human body is best equipped to run on carbs and that fats are dangerous [3]. While it is true that your body utilizes carbs much faster and easier than it does the other two macros (fats and protein), there are two problems with this thinking:


1) Carbs are not an essential nutrient unlike fats and protein

Essential nutrients are those your body can't live without. Research shows nine amino acids, two fatty acids (omega-3 and omega-6), thirteen vitamins, and fifteen minerals are essential for human health [4]. As you can probably tell, carbs are not on the list.

That's because your body is capable of making glucose from other nutrients, like protein. It's also able to run on fatty acids and make ketones to replace glucose. Glucose is an essential nutrient, but it does not have to come from carbs, and that's the whole point here.

2) Some populations eat very little carbs

The Inuit people and Maasai have lived on diets very different from our own. The Inuit rely on sea mammals and fish with very little access to plant foods in the Arctic tundra. Maasai, on the other hand, consume mainly milk, meat, blood, honey, and tree bark. Despite their high-fat diets, studies show both the Inuit and Maasai have a low incidence of heart disease [5, 6].

When you take these facts into account, a high-fat, low-carb diet such as keto isn't really all that unnatural. It's simply different from what we've learned to eat.

All in all, we believe that keto as an alternative approach to nutrition is completely safe. The human body can adapt easily to different diets. What's more, most people would benefit from switching to a different way of eating. With the obesity epidemic in full swing, it's quite obvious that what we perceive as normal is not normal at all.

What About Ketosis?

Another point of concern with keto is the constant ketosis. As long as you follow the keto diet, you'll be in this metabolic state. This also means the level of ketones in your blood will be higher than usual. Some keto-ers are worried that this might leave a negative effect on their health, thinking that the highly acidic ketones will change their blood pH to unhealthy levels.

Well, a 2017 study involving 20 participants found that there were no changes in blood acidity after 4 months on the diet [7]. Such studies clearly show that ketones raised to normal levels do not affect health negatively. And besides, ketosis is not an abnormal metabolic state. It is completely natural and designed to keep you going in times of starvation which was common in the past.

Common Keto Concerns

Keto and ketosis are, in themselves, safe and natural. But there are things that can go wrong on keto and that depend on your health and diet quality. Newbies tend to make mistakes that can leave them feeling ill at the least and put their health in jeopardy at worst. With all that in mind, here we discuss some common keto concerns.

1. Nutrient deficiencies

The range of food choices on keto is limited. That's why if you don't play your diet carefully to include a variety keto food, you run the risk of nutrient deficiencies. Meats, dairy, eggs, nuts, seeds, and berries all contain nutrients you need to stay healthy. What's more, these foods contain more vitamins and minerals than plant foods.

But if you rely on butter and bacon to nourish you on your keto diet, then you'll have a problem. Fat is the central nutrient on a keto diet, yes. But it's not the be all and end all of ketogenic eating. Your body still needs plenty of protein, vitamins, and minerals to function normally. You can get these only from a variety of keto-friendly foods such as the ones we mentioned earlier.

Another less talked about nutrient worth noting is fiber. Fiber is an indigestible carbohydrate, which means it does not affect blood glucose or ketosis. It is essential for health despite not providing any nutritional value as it aids in gut motility and microflora balance. It's hard to get enough fiber on a keto diet because it excludes some of its best sources (grains and fruit). Eating low-carb veggies and taking fiber supplements help resolve this problem.

2. Ketoacidosis

Ketoacidosis is something not to be confused with ketosis. It's a state of abnormally high ketone levels that causes the blood to become acidic. In other words, it's extreme and uncontrolled ketosis. In worst case scenarios, ketoacidosis can be deadly.

Luckily, it rarely happens, and when it does, it's for the following reasons:

  • Alcoholism
  • Starvation
  • Type I Diabetes
  • Type II Diabetes (rare)

These conditions stop normal insulin production. When there's not enough insulin, your body can't use glucose or ketones for energy. As a response, your liver may start producing ketones uncontrollably as a response to this energy crisis. In people with a normal insulin response, this rarely happens, if ever.


3. High blood lipids

Most dietary guidelines recommend lowering fat intake to reduce the risk of cardiovascular problems like atherosclerosis, heart attack, and stroke [8]. Such advice came from the widely-held belief that dietary fats increase blood fats (lipids) which, in turn, lead to inflammation and hardening and clogging of the arteries (cardiovascular disease).

However, newer studies are bringing this theory into question [9]. These studies now claim that cardiovascular disease is a result of inflammation and not excessive fat intake. This was also evident by the Maasai and Inuit examples mentioned earlier. As for the effects of high-fat diets like keto on blood vessel health, studies actually show that these diets improve blood lipids and reduce inflammation [10].

4. Electrolyte imbalances

Electrolytes are substances that, when dissolved in water, conduct electricity. In your body, they include several key minerals and other compounds. They help conduct electrical activity between your muscle and nerve cells.

Electrolytes need to be in perfect balance for normal functioning.

Too much or too little of any electrolyte is called an imbalance and can, and often does, happen on keto. The reason keto dieters develop electrolyte imbalances is glycogen depletion and subsequent fluid loss. Glycogen is a simple sugar molecule that binds to water. You lose glycogen early in your diet and with it, you lose water and electrolytes.

The symptoms caused by electrolyte imbalances are referred to as the "keto flu." Luckily, this problem is only temporary on a keto diet. Within a week or two, your body will be able to hold on to electrolytes. But in the meantime, it's a good idea to stay well hydrated and take electrolyte supplements or eat electrolyte-rich foods to minimize the keto flu.

Who Should Be Careful with Keto?

The keto diet drastically changes how your metabolism works. You need to know whether your body can handle this change. There are rare diseases and conditions that make it impossible to live on a high-fat diet. Then there are those that warrant a bit of precaution. Here is a list of situations where you'd want to quit the idea of keto or be cautious:

Pregnant & breastfeeding

Animal studies show that the ketogenic diet negatively affects the development of the fetus [11, 12]. Studies on humans are rare for safety reasons. But there is one study on two pregnant women who followed the keto diet to control their epilepsy [13]. The diet helped control their seizures, and the babies developed normally in these pregnancies.

While the discussion on keto safety for pregnancy is still open, we suggest not following this diet while pregnant. The same goes true for breastfeeding as there are no studies examining the impact of keto on breast milk quality.



Keto is great for diabetes. However, you need to take necessary precautions when starting the diet. As already mentioned, people with diabetes (especially type 1) are at a higher risk of ketoacidosis. To reduce your risk, make sure that you are taking your insulin medication as prescribed.

Your doctor may also adjust your insulin dose when your blood glucose drops on keto. This way, you'll prevent hypoglycemia. But in the long-run, keto helps balance out blood sugar and increases insulin sensitivity. You just need to play it carefully when you start keto with diabetes.

People with fat metabolism disorders

These rare genetic disorders affect the ability to digest fat due to a lack of fat-digesting enzymes. While people with these rare conditions can survive with the help of medication, it's not wise to follow keto when fat metabolism is compromised. Luckily, these disorders are rare, and most people can metabolize fat easily.

Bottom Line

When followed correctly, the keto diet is perfectly safe and even beneficial. Current evidence shows there are no complications from following the diet or being in ketosis. When people do develop problems on keto, it's usually from poor food choices and health problems.

Avoid eating the same meal over and over to avoid nutrient deficiencies. Also, keep an eye on your insulin, blood glucose, and ketone levels if you have diabetes. Those with rare conditions and pregnant and breastfeeding women may want to skip the diet for now. You may also want to tell your doctor you are following the diet if you suffer any medical condition.

Excluding the rare and short-term side effects, we believe you don't need to think twice about going keto. The diet provides more benefits than we can count. From weight loss to reduced inflammation and deadly disease risk, the keto diet is great for many things.


  1. Mayo Clinic Staff. Nutrition and healthy eating. 2017 February 7 -
  2. Wheless JW. History of the ketogenic diet. 2008 November -
  3. National Institute on Aging. Important Nutrients to Know: Proteins, Carbohydrates, and Fats. 2019 April 29 -... View all references

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