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? 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. 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.

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. 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. 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.

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 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. This is because in people with diabetes, ketopausal disease can more easily trigger a dangerous condition called ketoacidosis. This 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.

Dehydration and loss of electrolytes

Woman drinking water

Electrolyte imbalances are also common if keto diet followers are unaware of the need for hydration. It is important to stay hydrated in the keto diet, especially at first. 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. Then you experience side effects of the keto diet like slower cognition, memory loss, headaches and confusion. 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. 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. 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. Without fiber-rich foods, you may begin to experience changes in your gut, including difficulty moving your gut and eventually constipation. 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.

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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