9 Potential Intermittent Fasting Side Effects

Intermittent Fast

Intermittent fasting is a phrase that refers to eating schedules that include frequent periods of fasting in which people eat very little or no calories.

The following are some of the health benefits linked to intermittent fasting, according to studies:

  • weight reduction
  • Cardiovascular disease risk factors have decreased
  • lowering blood pressure
  • Improved insulin sensitivity was seen.
  • Oxidative stress markers decreased
  • higher blood sugar control

These results have driven the increased use of intermittent fasting regimens, such as:

  1. time-restricted feeding 
  2. alternate-day fasting 
  3. periodic fasting

You’re probably interested in finding out whether intermittent fasting has negative effects if you’re considering trying it.

The simple answer: Intermittent fasting is typically safe for most people. However, research has shown that periodic fasting has a few minor drawbacks. It’s also not the best option for everyone.

This post summarizes the possible side effects of intermittent fasting.

1. Hunger and desire for food

It’s no surprise that hunger is one of the most frequent negative effects associated with intermittent fasting.

You may feel more hungry if you reduce your calorie intake or go for extended periods without eating.

An experiment involving 112 participants divided them into two groups: one that followed an intermittent energy restriction regimen and another that didn’t. Every week, they consumed 400 or 600 calories on two nonconsecutive days for a year.

Those who ate a low calorie diet with restricted daily calorie intake had lower hunger levels than people who consumed a high-calorie, low-fat diet.

According to studies, hunger is a typical symptom that people experience during the first few days of a fasting practice.

In a survey of 1,422 individuals who undertook fasting regimens of four to twenty-one days, one study found that hunger problems tended to occur only during the first few days .

As a result, symptoms such as hunger may go away as your body adjusts to recurring fasting.

2. lightheadedness Headaches and

Intermittent fasting can cause headaches. They’re most common during the first few days of a diet.

In 2020, a review of 18 studies on people using intermittent fasting regimens was performed. Some participants in the four studies that reported side effects complained of mild headaches.

Fast headaches, on the other hand, are quite unusual. Researchers discovered that they are generally situated in the frontal part of the brain and that the discomfort is usually mild or moderate.

Furthermore, individuals who suffer from headaches frequently get them while fasting than those who don’t.

According to doctors, headaches are common during intermittent fasting and may be due to a number of causes. Caffeine withdrawal has been linked to low blood sugar and headaches.

3. Digestive problems

Digestive difficulties, including constipation, diarrhea, nausea, and bloating, are possible symptoms if you do intermittent fasting.

It’s possible that reducing food consumption on certain types of intermittent fasting might have a detrimental effect on your digestion, causing constipation and other problems. Intermittent fasting regimens changes in eating habits as well, which can cause bloating and diarrhea.

A lack of water, another frequent side effect linked to brief-term fasting, can exacerbate constipation. As a result, while following this regimen, it’s critical to stay adequately hydrated.

Choosing foods high in fiber, such as fruits and vegetables, may also help prevent constipation.

4.Irritability and other mood swings

When you practice intermittent fasting, some people may become irritable and moody. When your blood sugar levels are low, you can become irritated .

During periods of calorie restriction or fasting, low blood sugar, also known as hypoglycemia, may occur. This might cause irritability, anxiety, and lack of attention.

A 2016 research in 52 women found that women were significantly more irritable during an 18-hour fast than when they were not fasting.

Surprisingly, the women reported a greater feeling of achievement, pride, and self-control at the conclusion of the fast period than they did at the beginning.

5. Getting tired and having little energy

Some people who participate in various forms of intermittent fasting complain of tiredness and low energy.

When you’re following an intermittent fasting plan, keep in mind that if your blood sugar levels are too low, you may feel tired and powerless. In addition, some people may have difficulties sleeping when they fast regularly, which can lead to daytime tiredness.

However, some research suggest that intermittent fasting can help to relieve tiredness, especially if your body is used to regular fasting periods.

6. Bad breath problem

During intermittent fasting, some individuals develop unpleasant breath. This is caused by a lack of saliva flow and the build-up of acetone in the breath.

During fasting, your body utilizes fat for energy. Acetone is a by-product of fat breakdown, so it levels up in your blood and breath during fasting.

Furthermore, dehydration — an indication of intermittent fasting – can result in dry mouth, which is linked to foul breath.

7. Restless sleep

Sleep difficulties, such as being unable to fall asleep or remaining asleep, are one of the most prevalent side effects associated with intermittent fasting.

In a study published in the Journal of Nutrition and Metabolism, 1,422 people who engaged in fasting regimens of 4–21 days were observed. The researchers discovered that 15% of participants had sleep difficulties as a result of fasting. They reported this more frequently than other adverse effects.

Fatigue is more likely after the first few days of an intermittent fasting plan since your body expels a lot of salt and water through your urine. Dehydration and low salt levels can also result from this.

In fact, other research has shown that skipping meals had no impact on sleep.

A study published in 2021 examined 31 overweight individuals who followed an alternate day fasting plan together with a low-carb diet for 6 months. The study found that sleep quality and duration, as well as insomnia severity, were not affected by this strategy.

The same year, another 2021 study had similar findings.

8. Dehydration

During the first days of fasting, the body releases a lot of water and salt in the urine, as previously stated. Natural diuresis or natriuresis of fasting is the term for this natural process .

If this happens to you and you don’t replace the fluids and electrolytes you lost through urination, you risk becoming dehydrated.

Furthermore, those who practice intermittent fasting may forget to drink or not drink enough. This is especially likely when you first start an intermittent fasting plan.

Water should be taken in throughout the day and your urine should be checked for color to stay adequately hydrated. It should ideally be a pale lemonade color. A dark-colored urine may indicate that you’re dehydrated.

9. Malnutrition

Intermittent fasting is not without risk, and it may result in malnutrition if done incorrectly.

Malnutrition can result if a person goes without food for long periods of time and doesn’t replace their nutrients. The same may be said about unbalanced continuous energy restriction diets.

On a lot of intermittent fasting regimens, people are typically able to meet their calorie and nutrient needs.

However, if you don’t plan your fast or practice it meticulously for a lengthy period of time, or if you severely limit your calorie intake, you may end up malnourished as well as suffer from other health issues.

That is why it’s critical to eat a well-balanced, nutritious diet while intermittent fasting. Never limit your calorie intake excessively.

A healthcare professional with knowledge in intermittent fasting can help you develop a safe plan that provides the right number of calories and nutrients for your needs.

Who should avoid intermittent fasting?

Intermittent fasting may be a good option for some people, but it’s not appropriate or safe for others.

If you follow an intermittent fast, you might be at risk of serious health issues.

Intermittent fasting is harmful for the following individuals :

  • People who are pregnant or breastfeeding/chestfeeding
  • toddlers and teenagers
  • Some elderly people, especially those with muscle or nerve problems.
  • people with immunodeficiencies
  • people with present or past eating problems
  • people with dementia
  • People with a history of traumatic brain injury or post concussive syndrome

This is not an exhaustive list, and there are exceptions. For example, pediatric epileptologists have employed fasting to treat epilepsy.

It’s critical to discuss the benefits and dangers of intermittent fasting with a medical professional if you have a medical condition or are currently taking medications.

Some individuals may be more susceptible to negative effects related to fasting, so it’s critical to find out whether or not intermittent fasting is the best option for you.

If you experience persistent adverse effects from intermittent fasting, this may suggest that it isn’t suited to your body. The following are some of the possible adverse effects:

  • voracious hunger
  • nausea
  • irritability
  • headaches
  • fatigue
  • faintness

If the program makes you feel unhappy, don’t go on to intermittent fasting.

Despite the fact that this eating method has been linked to health advantages, there are a variety of other things you may do to improve your health that don’t include fasting.

Eat a balanced and nutritious diet, get enough sleep, exercise regularly, and manage stress — these are far more essential for maintaining general health.

The bottom line

Intermittent fasting has been linked to a variety of health advantages, including reduced blood pressure and cholesterol levels, weight reduction, improved blood sugar control, and more.

Although intermittent fasting is typically considered safe, it has been linked to adverse effects such as hunger, constipation, irritability, headaches, and foul breath.

Plus, experts advise certain people to avoid intermittent fasting. People with eating disorders or who are pregnant or breastfeeding should avoid it.

If you’re interested in intermittent fasting, talk to your doctor first to make sure it’s a good idea for you.