Dangers Of Intermittent Fasting

In this article we will be talking about dangers of intermittent fasting. If you’re thinking about trying intermittent fasting, you’re probably wondering if it has any negative consequences.

The Truth About Intermittent Fasting - Elite Medical Center

The short answer is that most people can safely fast intermittently. Intermittent fasting, however, has been shown in studies to have some minor side effects. Highlighted below are specific dangers of intermittent fasting.

 Cravings and hunger

Starvation is one of the most known dangers of intermittent fasting, which comes as no surprise. You may experience increased hunger if you reduce your daily caloric intake or go long periods without eating.

Some 112 people were randomly assigned to an intermittent energy limit group in a study. For a year, they ate 400 / 600 calories on two nonconsecutive days each week. These individuals reported feeling more hungry than those who followed a low-calorie diet with constant calorie restriction. According to studies, hunger is a common symptom people encounter during the first few days of a fasting regimen.

In a 2020 study, 1,422 people took part in fasting regimens that lasted 4–21 days. Only over the first few days of the treatments did they show signs of hunger. As a result, hunger symptoms may fade as your body adjusts to frequent fasting periods.

 Lightheadedness and headaches

 Of all the known dangers of intermittent fasting, lightheadedness and headaches are not uncommon. They usually happen in the first several days of a fasting regimen.

In a special study released in the year 2020, researchers examined 18 papers including persons who practiced intermittent fasting. Some individuals in the four studies who reported adverse effects claimed they experienced moderate headaches.

Researchers have discovered that “fasting headaches” are frequently situated in the frontal area of the brain, with pain that is mild to moderate in severity.

Furthermore, those who suffer from headaches often are more likely to suffer from headaches when fasting than those that don’t. Low sugar levels and caffeine withdrawal have been linked to migraines during intermittent fasting, according to studies.

Problems with digestion

 If you perform intermittent fasting, you may have digestive difficulties such as constipation, diarrhea, nausea, and bloating.

Digestive problems? Try probioticsThe decrease in food intake that various intermittent fasting regimes entails may have a detrimental impact on your digestion, resulting in constipation and other unpleasant side effects. Additionally, dietary modifications linked with intermittent fasting regimens might result in bloating and diarrhea.

Constipation can be exacerbated by dehydration, another typical adverse effect of intermittent fasting. As a result, it’s critical to keep well hydrated while fasting intermittently. Constipation can be avoided by eating nutrient-dense, fiber-rich meals.

Angry moods and other mood swings

 Of the dangers of intermittent fasting, anger is also very prominent. When people practice intermittent fasting, they may suffer irritation and other mood swings. When your glucose levels are low, you may get irritable.

Hypoglycemia, or low blood sugar, can occur during times of calorie restriction or fasting. Irritability, anxiousness, and poor focus are all possible outcomes.

An 18-hour fasting phase made participants substantially more irritable than a non-fasting time, according to a 2016 research of 52 women.

Interestingly, the researchers discovered that, though the ladies were irritated towards the conclusion of the fasting period, they also felt a greater feeling of accomplishment, pride, and self-control than they did at the beginning.

Tiredness and a lack of energy

intermittent fasting getting tiredSome persons who practice various forms of intermittent fasting feel tiredness and poor energy levels, according to studies. Intermittent fasting might make you feel fatigued and weak due to low blood sugar. In addition, intermittent fasting may induce sleep problems in certain persons, resulting in fatigue during the day.

Intermittent fasting, on the other hand, has been shown in some studies to reduce tiredness, particularly when your body adapts to regular fasting intervals.

Breath problems

Bad breath is an uncomfortable side effect that some individuals experience when they fast intermittently. Limitation in salivary flow and an increase in acetone in the breath cause this.

Fasting enables your body to burn fat as a source of energy. Because acetone is a byproduct of fat metabolism, it accumulates in your blood & breath while you fast.

Dehydration, which is a sign of intermittent fasting, may also produce dry mouth, which can contribute to foul breath.


Disruptions in sleep

According to some study, sleep problems, such as inability to fall or remain asleep, are one of the most prevalent dangers of intermittent fasting.

In a 2020 research, 1,422 individuals took part in fasting regimes that lasted 4–21 days. Fasting caused sleep problems in 15% of the individuals, according to the research. This was mentioned more often than other adverse effects.

Because your body excretes huge amounts of salt & water through the urine, fatigue may be more prevalent in the early days of an intermittent fasting routine. Dehydration & low salt levels might result as a result of this.

intermittent fasting-sleep distruption

Other researches, on the other hand, have found that intermittent fasting has no effect on sleep.

A research published in 2021 looked at 31 obese adults who fasted on alternate days while simultaneously eating a low-carb diet for six months. This regimen had no impact on sleep quality or length, or the severity of insomnia, according to the research. Similar findings were found in a research conducted in 2021.


Of all the dangers of intermittent fasting, one of the most common is dehydration. As previously stated, the body discharges a lot of water & salt in the urine during the first few days of fasting. Natural diuresis, also known as fasting natriuresis, is the name given to this process.

You might get dehydrated if this occurs to you now and you don’t restore the water and electrolytes you removed from pee.

Dehydration and intermittent fasting

In addition, persons who practice intermittent fasting might forget to eat or drink insufficiently, especially if you are a beginner.

Drink water each day and keep an eye on the color of your urine to stay adequately hydrated. It should ideally be the hue of light lemonade. You may be dehydrated if your urine is black in color.



Intermittent fasting, if done incorrectly, can result in malnutrition.

Malnutrition may occur when a person fasts for lengthy periods of time and does not refill their body with necessary nutrients. The same may be said for unplanned, long-term energy restriction diets.

On various forms of intermittent fasting regimens, people are typically able to satisfy their calorie and nutritional demands.

However, if you don’t properly plan or execute your fasting program over a lengthy period of time, or if you purposefully restrict calories to an excessive degree, you risk malnutrition and other health problems.

That’s why, when fasting intermittently, it’s critical to eat a well-balanced, nutritious diet. Make sure you’re not restricting your calorie intake too much.

A healthcare practitioner who is familiar with intermittent fasting can assist you in developing a safe diet that offers the proper quantity of calories and nutrients for you.

Who should refrain from fasting on a regular basis?

Intermittent fasting could be a good idea for some people, but it isn’t suitable or safe for others.

Intermittent fasting has the potential to cause severe adverse effects in some persons.

Intermittent fasting is typically advised against by healthcare professionals for the following people:

People with immunodeficiency • People with existing or past eating disorders • People with dementia • Those with a history of brain trauma or post concussive disorder • Those with a history of brain trauma or post concussive disorder • Those with a history of brain trauma or post concussive disorder • Those with a history of brain trauma or post concussive disorder • Those with a history of brain trauma or post

There are outliers to this list, which is not exhaustive. Fasting, for example, has been used to treat seizures in youngsters by medical professionals.

If you have a health challenge, you will need to talk to a trusted health professional about the advantages and dangers of intermittent fasting. Because some people are more susceptible to the negative consequences of fasting, it’s vital to figure out if intermittent fasting is okay for you.

Furthermore, if you have long-term adverse effects from intermittent fasting, it might be an indication that it isn’t effective for you. The following are examples of possible negative effects:

Nausea, irritability, migraines, fatigue, and faintness are all symptoms of extreme hunger.

If you’re unhappy with intermittent fasting, don’t keep doing it.

Even though fasting has been linked to health advantages, there are many more ways to improve your wellbeing that do not require fasting.

Following a well-balanced and healthy diet, getting enough sleep, exercising regularly, and managing stress are all far more essential for overall health.

Last Words

Intermittent fasting has been associated to a variety of health advantages, including reduced risk factors for heart disease, loss of weight, better blood sugar levels, and more.

Intermittent fasting is usually seen to be safe, although studies have shown that it can cause hunger, diarrhea, irritability, migraines, and foul breath.

In addition, several healthcare specialists advise against intermittent fasting. Pregnant women, nursing mothers and individuals with some eating disorders fall under this category.

If you’re thinking about attempting intermittent fasting, talk to your doctor first to be sure it’s a safe and healthy option for you. Dangers of intermittent fasting may not be dominant, but they are significant and should always be taken serious!