Side effects of keto diet

The prevalence of obesity has increased sharply over the decades. Obesity increases the risk of type 2 diabetes, hypertension, cardiovascular disease, osteoarthritis, sleep apnea and even some cancers. Individuals are also prone to psychological problems such as low self-esteem and depression. People, therefore, opt for extreme dietary interventions that lead to rapid weight loss. One such extreme dietary intervention that has gained popularity in recent years is the ketogenic diet. But is the keto diet really good for you or does it have hidden dangers? There are many side effects of the keto diet.

By now you’ve probably heard all about the ketogenic diet, the high-fat, low-carb (below 50g/day) diet that everyone is talking about. While the benefits of a keto diet are fairly well-known weight loss and appetite suppressants, keto advocates usually minimize the disadvantages and dangers that it may bring. Here are some things you should know about a ketogenic diet before trying it out as a way to lose weight. Yes, you could lose weight, but the following side effects of keto diet or complications, and even the serious health consequences that many are not aware of, should also be kept in mind.

Keep reading to find out the truth about the negative effects of a keto diet.

Also read: 12 best weight loss activities

What is a keto diet?

Pastry, avocado and boiled egg on plate

A keto diet is a diet that contains ultra-low carbohydrates and high fat foods. It limits the total number of carbohydrates to just 20 or 30 net grams of carbohydrates per day. This is equivalent to one piece of fruit or half a pastry.

The keto diet is different from other low-carb diets because instead of focusing on protein, it focuses on fat. Fat consumes 60 to 80 percent of daily calories, with 5 to 10 percent of carbohydrates and 10 to 30 percent of protein.

So, what happens to your body when you eat keto and how does the body burn fat in ketosis? When you reduce your carbohydrate intake, the desired source of energy in your body, you need your body to suddenly switch to using fat as an energy source. This raises your blood ketone levels and puts you into a ketosis state, hence the name “keto diet”. Once this change happens, you will start to lose weight.

Is the keto diet safe long term?

A study published in the scientific journal Nature Metabolism, conducted on mice, explained that long-term practice of the keto diet has a bad effect on health.

In mice that were on this regimen for a shorter time, their health improved, that is, the inflammation in the body decreased, and the metabolism accelerated. But after a few months on the keto diet, the condition changed – the mice became obese, their metabolism slowed down, and the inflammation in the body greatly increased.

The ketogenic diet is based on eliminating carbohydrates and increasing the intake of healthy fats such as avocados, salmon, nuts, all in order to bring the body into a state of ketosis in which it uses fats as a fuel or energy source, not sugars and carbohydrates.

There is a fear among health professionals that such high intakes of unhealthy fats in the keto diet would have a long-term negative effect. This is because when overweight people lose pounds, no matter how they do it, they often end up with better blood lipids and blood glucose levels.

The keto diet is also extremely low in certain fruits, vegetables, grains and legumes that are commonly considered healthy. Without these foods, people on a diet may be deficient in fiber, certain vitamins, minerals, and phytochemicals found only in those foods.

Keto, as a low-carb diet, can lead to significant long-term side effects on human health, such as weakening of the bones and an increased risk of chronic diseases that ruined lifes. It’s not bad to switch to a keto regimen from time to time, but for health, it’s still best to eat varied, seasonal, local and moderate.

How long is it safe to be in ketosis

The keto diet is not limited in time but we do not recommend it in the long run, especially for beginners whose bodies are not used to low carb intake.

You can do it for 3,6,10 weeks, it is individual and depends on the desires and the amount of subcutaneous fat. We recommend to avoid it, but if you really want to do keto, then you should follow the diet for max 6 months before reintroducing carbs back to your diet. Although less than that would be better.

What is important is that when you are on ketosis to be, in ketosis, when you are charging, you are charging so that you capitalize on that charging and that you use it as a component purposefully and not as killing in chips, gummy candies and similar nonsense.

When filling, fill yourself with food that really replenishes glycogen and stay away from garbage. Of course, treat yourself a little, but base the filling on potatoes, rice, gnocchi, oatmeal, pasta, ice cream.

Side effects of the keto diet

Keto flu

People on the keto diet often find that they have symptoms as their bodies adjust to their diet. Experts say this transition period is no joke.

When your body first goes into ketosis, you may experience a number of side effects and symptoms of the keto diet called keto flu. These include fatigue, dizziness, vomiting, fainting, poor sleep, difficulty exercising, and constipation, all stemming from extreme carbohydrate restriction.

These symptoms usually subside after the body adjusts to reliance on fuel fats. It can take anywhere from a few days to several weeks.


If you have type 1 or 2 diabetes, you should not follow a keto diet unless you have your doctor’s permission and strict supervision. Ketosis may actually be helpful for people who have problems with hyperglycemia, but you need to be very aware of your blood sugar and check your glucose level several times a day to avoid the occurence of symptoms.

This is because in people with diabetes, ketopausal disease can more easily trigger a dangerous condition called ketoacidosis. Notice that ketosis vs ketoacidosis are two different terms.

Ketoacidosis happens when the body stores too much ketone (an acid formed as a byproduct of burning fat) and the blood becomes too acidic. That can damage the liver, kidneys and brain. If left untreated, it can be fatal.

Ketoacidosis has also been reported in people without diabetes who have followed a low carb diet, although this complication is quite rare. Symptoms of ketoacidosis include dry mouth, frequent urination, nausea, bad breath and difficulty breathing. If you feel this while following a keto diet, contact your doctor immediately to avoid dangers.

Dehydration and loss of electrolytes

Woman drinking water

Electrolyte imbalances are also common symptoms of a low-carb diet if keto followers are unaware of the need for hydration. It is important to stay hydrated in the keto diet, especially at first because it can lead to many dangers. As you limit carbohydrates, your body generates less insulin, and glycogen stores (how carbohydrates are stored) are consumed in the muscles and liver.

For every 1 gram of glycogen consumed, you lose about 3 grams of water. Because of this, your kidneys release more water, and with it electrolytes such as magnesium, calcium, sodium and potassium.

Unbalanced electrolytes can lead to muscle cramps, irregular heartbeat, arrhythmias, fatigue, cognitive distortions and lack of body temperature control. Some people will also be more likely to get kidney stones while on a keto diet because of insufficient hydration.

Bad breath

During ketosis, your body produces ketones or byproducts of the fat-burning process. Your body uses several tactics to remove ketones from the body, including exhalation.

When your lungs excrete ketones, you can smell the acetone. Due to this fat burning process, you may develop bad breath while in ketosis. Drink plenty of fluid to keep your mouth hydrated and reduce the risk of bad breath. If the situation becomes particularly stinky, you can use refreshing sugar candy or chewing gum to cover up the situation.

Dizziness on keto

Your brain works on glucose (a simple form of carbohydrates). When you cut out carbohydrates, your body must create carbohydrates so that it breaks down other parts of the body.

You may be feeling dizzy on keto approximately after a month. Then you also experience more side effects of the ketogenic diet like slower cognition, memory loss, headaches, confusion, and othes negatives.

Also, those suffering from depression and anxiety may have higher levels of these periods when they do not eat carbohydrates regularly. Therefore, a keto diet may not be the best choice for those with mental health problems.

Nutritional deficiencies

The reason why you eat a balanced diet is to obtain the various nutrients your body needs to stay healthy. A balanced diet includes fruits, vegetables, dairy products, protein, cereals, legumes, nuts and seeds. You can eat all this on a low-calorie diet and lose weight successfully.

However, on the keto diet cereals, legumes and fruits are largely eliminated (berries, watermelons and apples are rarely allowed). These food groups provide a variety of nutrients, including fiber, vitamins, minerals and antioxidants such as vitamins A and C.

It is also known that people on keto diets have constipation due to lack of fiber in their diet. Keto is not a great long-term diet because it is not a balanced diet, so it may have serious side effects and doesn’t lead to long-term success in fat loss. A diet without fruits and vegetables will result in a long-term deficiency of micronutrients, which can have other consequences.

Keto diet and muscle loss

A man with his arms crossed stands in front of a blackboard on which strong hands are drawn

The longer you have ketosis, the more fat you burn. Unfortunately, you can also start losing muscle tissue.

While protein is considered a builder of muscle strength, your muscles need carbohydrates for adequate formation and maintenance. Without these carbohydrates, your body can begin to break down muscles. As your body begins to destroy muscle as it enters ketosis, your heart, which is also a muscle, can be damaged in the process.

In addition, you may find it difficult to eat adequate calories on a daily basis because the fat is very saturated. Some even choose to fast for a few hours a day. While this can help with weight loss, your body needs those calories for proper maintenance. Without them, the muscles themselves can burn to gain energy, and this can accelerate muscle loss.

Keto diet increases risk of heart disease and diabetes

Loss of heart muscle may not be the only cardiac-related keto diet hazard. If you have high blood pressure and take medication, therapy mixed with diet can cause abnormal results of a low blood pressure test.

Talk to your doctor before starting a keto diet to avoid low blood pressure, chest pain or heartburn. This condition can be dangerous, even deadly. This is why many health professionals are concerned about people on the keto diet. Especially those who try it without the guidance of a doctor or nutritionist.

Doctors say a high-fat diet like this can increase cholesterol levels, and some studies show they increase their risk of diabetes. Some have even called it a “cardiologist’s nightmare.”

A study of 25,000 people presented at the Congress of the European Society of Cardiology in Munich suggested that people with the lowest carbohydrate diet were at the highest risk of dying of cancer, cardiovascular conditions and all other causes.

Another study, published in the journal Lancet, also found that people who followed a low-carbohydrate diet and animal protein had a higher risk of early death compared with those who consumed carbohydrates in moderation.

Kidney stones and kidney damage

If left untreated or reversed, dehydration can lead to acute kidney injury. However, this is not the only way a keto diet can endanger the kidneys. Kidney stones or kidney damage can also be side effects of the keto diet.

High levels of nitrogen created by excess protein can also increase the pressure in your kidneys. This can lead to the formation of more stones and damage the kidney cells.

People with kidney, liver and gout problems should be cautious when embarking on such a diet. They may increase the risk of further kidney failure, burden already-damaged liver, or cause gout.

Constipation, diarrhea, and bowel changes

Eliminating most fruits and vegetables can have other consequences. On keto, without fiber-rich foods, you may begin to experience changes and side effects in your gut, including difficulty moving your gut and eventually constipation or diarrhea.

The occurrence of diarrhea can be caused by the gallbladder, an organ that creates bile to break down fat in the diet. Diarrhea can also be caused by a lack of fiber in the diet, and this can happen when someone throws out carbohydrates (such as whole-grain bread and pasta) and is not supplemented with other fiber-rich foods, such as vegetables.

It can also be caused by an intolerance to dairy or artificial sweeteners. These are things that you may be eating more because of switching to a low carb lifestyle.

Weight gain

Side effects of the keto diet

Because the keto diet is so restrictive, health experts say it is not a suitable diet to follow in the long run. But the problem is that most people will regain a lot of the weight they have lost as soon as they get back on carbs. This is a problem with any diet, but it seems to be especially common with ketosis.

These types of weight fluctuations can also contribute to an irregular diet or may worsen an already unhealthy diet. The cause of these weight changes associated with the keto diet may be the loss of muscle mass, especially if you eat a lot more fat than protein. You will lose weight, but it can actually be a lot of muscle, and because muscles burn more calories than fat, it will affect your metabolism.

When a person leaves the ketogenic diet and gains most of their original weight, that weight is often not in the same proportions as before. Instead of muscle, you are likely to gain fat. People return to their original weight, but no longer have the muscle mass to burn calories as before. This can have lasting effects on resting metabolic rate and on long-term weight.

Side effects of keto pills

Keto pills contain exogenous ketones. They provide the body with ketone bodies. The goal is, in theory, to achieve ketosis without drastically reducing carbohydrate intake and enhancing the slimming effect of the diet.

However, there is no solid evidence that this actually works, it could in fact have just the opposite effect. Some studies suggest that the consumption of exogenous ketones is an effective way to help us reach the state of ketosis, but this will only have an impact if it is accompanied by the keto diet.

Furthermore, the body has a system that controls the amount of ketogenic bodies present in the blood since an excess could make the blood too acidic. If through these supplements we give the body enough ketogenic bodies, it will inhibit the processing of body fat to produce more. And with that, we will destroy the goal of losing weight.

Some preliminary studies have shown positive effects on weight loss, although for another reason: according to a study published in the journal Obesity, the consumption of exogenous ketones decreases the feeling of hunger, helping to eat less and thus lose weight.

Overall, the arguments in favor of the slimming effect of these pills are few, incomplete and contradictory.

Mostly, the consumption of exogenous ketones in the form of keto pills is safe and has no risks, as long as you buy a regulated product in an authorized store and not the first pills that we find online.

However, there are some possible associated risks. To facilitate their absorption these compounds often contain high amounts of salts such as sodium, magnesium or calcium. These minerals, in limited amounts, are part of a healthy diet, but if we go too far, they can cause some health problems, such as cardiovascular problems.

How long do keto side effects last?

Unfortunately, it is not possible to predict whether and what side effects and dangers of the keto diet you will have. The strength of the side effects is also very individual. It depends a lot on how you have fed yourself so far.

If you were a fast food and ready-made product junkie, you will probably have more trouble making the transition than someone who has a generally varied diet on unprocessed foods (but simply high in carbohydrates). Much also depends on how much sugar you’ve consumed before.

The duration of the change and the duration of the side effects is also very individual. For most of them, the changeover took place after two weeks. For some it is faster, for others, it can take up to four weeks for the body to get used to it.

Who is a ketogenic diet suitable for?

Not all people are suitable candidates for the keto diet, especially those with chronic conditions such as high blood pressure, diabetes or other conditions.

If you are seriously thinking about long-term weight loss, a ketogenic diet is not the right choice for you. It is also unsuitable for pregnant and breastfeeding women or mothers with irregular menstrual cycles. The keto diet is also not recommended for active athletes as it can cause muscle loss.

This diet can result in major changes in metabolic and other body systems. It can also change the effectiveness of medications that some people take. So, if you have any medical condition, it would be best to talk to your doctor before you decide to try a keto diet.


These symptoms do not affect everyone. So if you are interested in the keto diet, try it and see how you feel. However, the diet is restrictive and can be difficult to follow. In addition, there is no research to show how keto affects your overall health or risk of heart disease.

If you realize that this diet does not suit you, it is not advisable to start consuming a larger amount of carbohydrates immediately.

When you return to a normal diet, carbohydrates should increase slowly. There is no going back to old habits overnight. Otherwise, you will probably experience weight gain. You will also feel terrible, with an influx of sugar that you are no longer used to.

Side effects of the keto or any other diet do not affect everyone equally. However, considering many reviews of the ketogenic diet, you shouldn’t ignore the keto side effects that can bring many dangers. So, before any diet, it would not be bad to be well informed or consult a doctor. It is also important to remember that no diet is worth your health, regardless of current trends.

Also read: What is fat fasting?


  1. You have provided very good information. Nowadays people are getting attracted towards it only for quick results of losing weight, regardless of all these side-effects.

    • That’s right. Aside from the fact that the keto diet can create all of these side effects, people also don’t realize that rapid weight loss is detrimental to health. Most of these regimens are based on the principle of losing subcutaneous water and glycogen stores, which will inevitably cause weight loss. But the real removal of fat deposits is more evident in the mirror than in the weight loss itself.
      You will look better if you lose five kilograms in a healthy way from fat deposits over a longer period of time, than 10 kilograms in a faster way by losing body fluids, muscle mass and, only finally, some fat tissue.


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