Can Intermittent Fasting Cause fatigue and Tips to Overcome Tiredness

Are you feeling fatigued, faint, or tired after starting a new Intermittent Fasting Schedule? If yes, then do not panic, you are not alone. 

Intermittent fasting is the most popular dietary plan or nutritional practice among A-list celebrities and fitness communities. 

This exceptional meal plan allows individuals to simply map out their eating and fasting practices into separate intervals. 

Intermittent fasting is not only celebrated as a quick way of losing a couple of extra pounds but also for benefits like preventing serious heart diseases and regulating blood sugar levels in patients with type 2 diabetes. 

But with all the glorified benefits of practicing the Intermittent fasting diet plan, indulging in a restrictive and calorie-deficit meal plan may make you feel extremely fatigued and faint throughout the day. 

In fact, consistently practicing intermittent fasting can lead to several unpleasant side effects like headaches, stomach ache, hunger, nausea, tiredness, fatigue, and in some severe cases leads to malnutrition. 

If you are someone who has just embarked on the intermittent fasting journey to maintain a clean bill of health but is feeling demotivated due to feeling fatigued and tired, we’ve got you covered. 

Here is how Intermittent Fasting can lead you to feel tired and fatigued along with some easy tips and tricks to overcome tiredness to have a headstart on your day.

What are the Three Kinds of Restrictions?

Before jumping on the list of tips and tricks to avoid feeling fatigued and tired while intermittent fasting it is best to know about the three different kinds of restrictions that can make you feel tired and fatigued. 

Generally, there are three forms of restrictions that are used by physicians and dietitians to help you achieve optimal weight loss and health benefits:

  • Dietary Restrictions (level 1)  that control what you consume 
  • Caloric Restrictions (level 2) that control your food and caloric consumption
  • Time Restrictions (level 3) that control when you are supposed to eat and when you are not

While Levels 1 and 2 are easily controlled by common dietary practices in the form of eating healthy and clean foods, Intermittent Fasting utilizes all three levels to help you achieve optimum sustainable weight loss results.

Why does Intermittent Fasting Cause Fatigue?

According to a 2017 study indicating the potential benefits and harm of Intermittent Fasting Energy Restriction, feeling tired and fatigued is among the first and the most common side effects of Intermittent Fasting. 

If you have just started your Intermittent Fasting Diet Plan and all of a sudden feeling exceptionally weak and unmotivated do not panic, as this problem can be easily overcome with simple steps. Here are five telltale signs of fatigue and tiredness caused by Intermittent Fasting:


Intermittent Fasting is a restrictive calorie deficit dietary practice that helps you map out your eating and fasting practices. 

In fact, Intermittent Fasting can lead to water loss and electrolyte depletion, especially during the early days of starting this practice. 

While water loss is a great way of promoting rapid weight loss, it can eventually lead to dehydration and in turn, make you feel fatigued and lethargic. 

Furthermore, as your body begins to shed increased fluids, the kidneys also start to excrete essential electrolytes like sodium, magnesium, potassium, and calcium. 

This imbalance of electrolytes is among the common causes of fatigue as these electrolytes control fluid balance, muscle function, and heart rate.

Low Blood Sugar Levels:

Low blood sugar levels can be the top reason you feel fatigued and tired during intermittent fasting. 

When abstaining from foods for prolonged periods of time your body begins to rely on ketones as a source of energy and fuel. 

But during the early stages of fasting your body is not used to such metabolic responses leading you to feel fatigued, tired, and lethargic leading to brain and exhaustion.

Slow Liver Function:

Your liver is an important organ that helps facilitate the metabolic process and regulate energy throughout the body. 

The liver stores essential minerals and vitamins that are crucial for the detoxification process of the body. 

Fatigue and exhaustion are directly linked to poor liver functions that may be caused by an unhealthy diet. 

Abstaining from foods that are rich in nutrients and micronutrients while intermittent fasting can lead to exhaustion and fatigue.

Vitamin B deficiency:

Vitamin B is essential for retaining and producing energy in the body that helps you adapt to the ketosis stage of fasting

A lack of vitamin B can lead to you feeling exceptionally lethargic and fatigued during intermittent fasting. 

A lack of carbohydrates in the body can lead to Vitamin B1 Deficiency which helps your body utilize ketones as an energy source. 

Vitamin B5 on the other hand helps facilitate cortisol production and adrenal function that helps balance and utilize fats as an energy source.

Stomach Acid Imbalance:

Imbalances in stomach acids can also make you feel exhausted, fatigued, and tired while intermittent fasting. 

Since intermittent fasting allows your stomach and digestive system to rest, it eventually leads to certain stomach acid imbalances.

Tips and Tricks to Overcome Tiredness During Intermittent Fasting:

It can be quite difficult to maintain consistency and stay motivated to continue intermittent fasting especially when you begin to feel tired and fatigued. 

If intermittent fasting tiredness has just triggered you to throw in the towel and quit, do not panic. 

Here are some simple tips and tricks you can follow to overcome tiredness caused by intermittent fasting to help you feel calm, soothed, and motivated enough to get back on track:

Review your Diet:

Fatigue and Tiredness are not only linked to the fasting periods of intermittent fasting but also to your diet. 

When practicing a restrictive calorie deficit diet plan like intermittent fasting, what you eat matters more than what you avoid. 

Hence it is best to review and focus on managing a healthy diet while consuming a nutritionally balanced diet to avoid fatigue and tiredness. 

Furthermore, you can adjust your eating schedules and meal plans based on your health requirements. You can either indulge in more food or less to maintain a clean bill of health and overcome tiredness.

Drink More Water:

Water is a great way of replenishing and energizing yourself. According to research, mild forms of dehydration can lead you to feel exceptionally tired and fatigued. 

This is because when you are dehydrated your blood pressure suddenly drops which in turn reduces the blood flow to the brain. 

This decrease in blood flow makes it difficult for the heart to work harder to efficiently supply nutrients, oxygen, and fluids to different cells which further makes you feel tired and fatigued. 

On top of that the symptoms of dehydration can also resemble the signs of hunger making intermittent fasting a lot more difficult than it is. 

Hence, the best way to avoid fatigue, overcome tiredness, and stay motivated during intermittent fasting is to drink more water and stay hydrated. 

If you don’t like the taste of burning plain water, you can also spruce up your drink by adding cucumber pieces, fresh fruits, or apple cider vinegar.


Coffee or other Caffeinated beverages is the easiest way of energizing yourself, especially when you are feeling sluggishly slow. 

Unsweetened caffeinated beverages are not only perfect for adding a jolt of energy but also suitable for an intermittent fasting diet. 

However, it is suggested to drink about 2 to 3 cups of coffee or somewhere between 300 to 400 mg of caffeine per day and avoid drinking coffee after 6 pm to maintain a healthy sleeping routine.

Get proper sleep:

A good night’s sleep is a perfect way of maintaining energy levels throughout the day and overcoming tiredness. 

According to the CDC guidelines, an average adult must sleep between 7 to 8 hours a day to have optimum productivity and maintain a clean bill of health. 

When it comes to intermittent fasting and sleeping schedules, the opinions are mixed. While some people swear that intermittent fasting is a great way of maintaining a healthy sleep cycle, others do not have such a pleasant experience. 

Some people claim that hunger induced by intermittent fasting can lead them to feel extremely sleepy and tired throughout the day, while others cannot fall asleep empty stomach. 

If you are someone who is unable to stay energized and active while intermittent fasting, it is best to adjust your sleeping schedule and drink tea before you go to bed to feel fuller.