Sleep and Fasting

Fasting can cause temporary mild sleep-related problems, but they will go away quickly as soon as you adapt to the new regime.

Trying to fall asleep on an empty stomach is never a pleasant experience, if you have ever been on a diet, or if you were punished as a kid to go bed without dinner, you know what a torture it can be. Eating is one of our natural, basic and mandatory needs, so when it is not satisfied correctly, it tortures our body and mind slowly until we eventually eat something again.

We mentioned the notorious method of punishment for kids which implies cutting off their last meal of the day since the abridgment of the food is considered as something difficult and challenging, it may be hard to believe that someone would do to that to himself intentionally, yet people do so.

For people who belong to various religious groups, fasting is more than a diet, it is a way of testing themselves, their will and faith, but it is also a way of purification. In recent years fasting got its five minutes of attention from people who are trying to do it from various non-religious reasons. Some believe that it will help them lose weight; others do it to detoxify their body or try out a new lifestyle. Regardless of the reasons, fasting is gaining more and more attention, which means that researchers are trying to find more about its pros and cons, the benefits and side effects. One of those mysteries is how fasting impacts sleep, is starvation a potential cause of sleep problems, or can it be beneficial in the long run.


What is Fasting?

Fasting is a rigorous regime of eating which can exclude all or some sorts of food and drinks during a certain period, and it is usually done as a way of religious observance. Many religious groups all over the world practice some form of fasting, some of them are Islam, Hinduism, Judaism, Orthodox Christians, and many others. One thing is common for all of them – they all believe that fasting is much more than just abstaining from food and drink, it strengthens their power of will, control, and behavior.

Water fasting, for example, refers to willing abstinence from all drinks and food, except for water, tea, and black coffee. Dry fasting or absolute fasting is abstinence from all kinds of food and drinks for a certain period. The most common and broad term is intermittent fasting which stands for various eating diets that cycle between periods of non-fasting and fasting. Intermittent fasting is a scientific term for Ramadan fast which lasts for 29 to 30 days in Islam.

Currently, many researchers are trying to prove if intermittent fasting can help people lose their weight and become a healthier option instead of permanent calorie restriction. When it comes to intermittent fasting, there are two main types of it:

  • Whole-day fasting refers to one-day fasts, and there are two forms of it. The first one is ADF, which stands for alternate day fasting, and it works in a way that the first 24 hours are for fasting, and then the next 24 hours are a non-fasting period. The second form is ADMF, alternate day modified fasting, also known as 5:2 diet, which consists of five non-fasting days and two days of fast in a week. Those two fasting days can be either modified or total fasting, but both options allow a daily intake of 500 to 600 calories.
  • Time-restricted feeding (TRF) means that eating is “allowed” only during a certain number of hours in a day. The most common form of it consists out of 16 hours meant for fasting, and 8 hours during which eating is recommended, on the same scheduled time each day. The strict form of it has 23 hours of fasting, and only one hour for one meal per day, while a more liberal form would be the one with 12 hours of fasting and 12 non-fasting hours.


Sleeping During Fasting

Just like with any other new routine that you are trying to establish, it takes time to adjust to it and actually see its benefits. Fasting can be extremely difficult and challenging if you are new to it, most people mention only the positive impact of it but forget to mention the struggles they experience on the road.

It is important to mention, and expect, that you would not be getting much sleep at the very beginning. Fasting can cause temporary sleep-related problems, but they are usually mild and go away quickly once your body adapts to the new regime. It usually takes as little as three nights to get back on track with proper sleeping as that is when our body slowly starts to adjust to fasting.

During the fast, you would not get much sleep but not due to starvation but because you will be full of energy. Sleep decreases during the fast, but that is not followed by the usual symptoms of sleep deprivation such as fatigue. On the contrary, you will wake up more easily, feeling energetic, and for some reason, you will feel better about yourself. So if you are thinking about starting a fast for the first time, do it during the weekend or when you do not have many important things to do since first few days and nights can be rough.

While we are abstaining from food, our body produces orexin which is a neurotransmitter in charge of keeping us alert, craving food, increasing body temperature and metabolism boosts. Studies performed on mice show that lower level of orexin can be connected to obesity regardless of the calorie intake, while a higher level of orexin can cause issues with falling asleep due to higher alertness. Lowering the level of orexin will make us feel more tired, which we can achieve by eating junk food. If you ever wondered why you suddenly feel tired after eating processed food, the answer is in glucose. Once glucose is released into our blood system, it smothers the flow of orexin which leads to fatigue and energy decrease.

Another hormone essential to fasting is adrenaline which keeps us awake and is also known for decreasing the appetite and causing weight loss by burning fat. Once we start to fast, out body stops working on energy that it gets from food which is carbs, and starts working on energy from fat called ketones, this phase is known as keto-adaptation, and it lasts for 2-3 days during which the adrenaline is released. If you have been relying on food as a source of energy for your entire life, sudden loss of it will lead to energy boost as a way of help to find and get more food. Once you go through this period your food cravings will decrease, and your sleep should be back to normal.

So it turns out that when we are fasting, we are able to function normally even without the optimal 8 hours of sleep per night thanks to higher levels of adrenalin and orexin. Our body will also need less recovery time as there is little or no food to digest, so it would not be wasting much energy on digestion. Many people say that they experience mental clarity during the fast, that is because our brain works more efficiently due to the production of a protein called brain-derived neurotrophic factor (BDNF).


How to Sleep Well During Fast?

Prepare yourself for an adjustment period and keep in mind your goal, it will be challenging, but it is not impossible, therefore here are some brief tips that can enhance your sleep during the days of fast.

  • Hydration – it is essential to stay well hydrated during the fast. Drinking plenty of water during the day will alleviate starvation and food cravings, but it will also help with your mood and mental state. Dehydration can only make things worse and be another issue that will keep you awake at night.
  • Listen to your body – although there are many kinds of research and studies that tell us what to expect, you can never be fully prepared since our bodies respond individually and have different sleep needs. To make this eating strategy work for you, you might need to customize it and make it more suitable for your needs.
  • Mindfulness – a lot of people reported that they have become more mindful due to fasting. Practicing mindfulness through breathing exercises and meditation can also be a good way of preparation for the fast, or help to cope with ongoing food cravings and diet.
  • Make your meals count – your body will accept and adjust to the new eating regime within a few days, and you would not feel the urge to overeat during the non-fasting periods. To really experience all the benefits of fasting, you need to eat healthily, and on time during the non-fasting days. It means that you need to limit the intake of sugar and sugary foods and eat food full of fibers, fruits, and vegetables, fish, nuts, etc. Eating well will pave the road to better sleep quality.
  • Binaural beats – two different tones are played in each ear via headphones, they increase the delta brainwaves which are usually connected to deep sleep, hence they will help you fall asleep quicker.


Intermittent Fasting Benefits

During recent years, intermittent fasting became popular even outside of its religious boundaries, and people started practicing it from various reasons. Many books and tv shows have been based on the 5:2 diet regime, which contributed to the growing number of people who fast.

It’s still unclear if fasting can help with weight loss, but studies have shown fasting has some health-related benefits. Studies have reported that there is a significant improvement in blood pressure, insulin sensitivity and level of cholesterol after intermittent fasting. Also, it lowers the risk of diabetes and coronary diseases, while fasting for more than two days can completely refresh and restart our immune system by regenerating new cells and clearing out the old ones. While we are starving, our body is trying to save energy, and it does that by recycling the old or damaged immune cells that are no longer needed.

Since food is banned during most fasts, our body is not getting any energy from it, instead, it has to dip into stored glucose found in muscles and liver. This process usually begins around eight hours after the last meal. After our body uses all the stored glucose, it starts burning fat as a way of creating new energy, which can result in weight loss. Another thing that also occurs during fasting is the process of detoxification because all the toxins that are stored in body fat are being dissolved and removed from the body. After fasting for a few days, our blood produces more endorphins, which is known as a happy hormone, so it can lead to a more positive mental well being.


Side Effects of Fasting

Fasting is not easy, and it is not for everyone, so we recommend consulting with your GP before starting with it. As there are some positive aspects of it, there are also negative ones, and many health risks have been related to fasting.

Once people who are used to having regular meals such as breakfast, lunch, dinner on a daily basis start to fast, besides hunger, they can experience stress, anxiety, headaches, which can all disrupt their sleep.

When fasting, our body is not getting enough fluid from the food, and that’s why many people experience dehydration. Another potential concern is heartburn. Food restrictions cause a reduction in stomach acid which usually destroys bacteria and digests food. Even when we think about the food or smell it during the fast, it tricks our brain to signal the stomach to produce more acid, causing heartburn.

While many advocate the idea that fasting can be related to weight loss, some people claim that fasting should not be used for those purposes. Fasting can result in quick loss of fluid, but not in a quick loss of weight because as soon as you start eating normal again, those pounds will come back. Some researchers believe that fasting can pull people away from healthy eating habits and trigger some eating disorders.


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