Intermittent fasting is all the rage these days in the health and fitness world, with numerous studies supporting its ability to reduce inflammation, improve cellular repair, and optimize gut health – while helping you lose weight. Also, cutting out certain foods can reduce snoring if that is an issue for you.
If you’ve just started intermittent fasting, you probably feel like you have more energy to work out and carry out your daily functions. You probably even complain less about not getting enough sleep, or feel like you don’t need the same amount of sleep as you used to. So do you need less sleep while fasting? The answer to that question is no!
The reason you don’t feel sleepy on fasting days is that your body is continually pumping out cortisol (stress hormone) during your fasted state. This is your body’s natural survival mechanism. If your blood sugar levels are too low or if you’re under stress, your body will release more cortisol to convert stored glycogen to glucose, bringing your blood sugar levels back up, without you eating anything.
The increased energy while working out, results from the glycogen in the muscles being converted to glucose – another evolutionarily designed survival mechanism. This is to activate our muscles and enable us to fight or flee from a potential threat. However, since we don’t have to hunt for our food, the excess cortisol being produced is adding to our stress load, resulting in sleep issues. If you’re having trouble sleeping on a fast, keep reading to understand why, along with what you can do to correct the situation.
How Does Fasting Affect Our Sleep?
Although limiting your food intake for a certain period can do your health wonders, intermittent fasting does come with its own set of potential side effects, especially for your hormone health. This mainly affects people with adrenal fatigue, thyroid problems, or other issues related to chemical imbalances.
Sleep deprivation and insomnia are common drawbacks of the chemical imbalances that arise from intermittent fasting, so let’s dig deep into fasting and sleep connection to determine if intermittent fasting is right for you.
Adrenal Hormones (Cortisol)
If you look at it from an evolutionary point of view, intermittent fasting was probably the norm when food wasn’t nearly as readily available, as it is now. There were no restaurants or grocery stores, nor were there schedules, lunch breaks, and structured meals. There is a high chance that our paleo ancestors did go 12 to 16 hours without eating regularly, and had lighter days when they ate less or nothing at all.
Therefore, it can be said that intermittent fasting is part of our evolutionary heritage – but it may not be the best wellness tool for everyone. This is because fasting elevates cortisol levels.
Food deprivation in general increases cortisol levels, which in turn increases vigilance. Again, this makes evolutionary sense. With an empty stomach, an animal has to stay alert for hunting and feeding opportunities.
Understanding Normal Sleep Architecture
Normal sleep architecture consists of light sleep, deep slow-wave sleep, and REM (dream stage) sleep cycles. Each stage can last from 5 to 15 minutes. Stages 1 and 2 of sleep are part of light sleep, whereas stages 3 and 4 include deeper slow-wave sleep. During stage 2, your heart rate starts to slow, and your body temperate drops. Stage 3 sleep, the transitional period between light and very deep sleep, is characterized by 20 to 50% slow brain waves, called delta waves.
Stage 4 includes greater than 50% delta waves and lasts for approximately 30 minutes. Stage 5 is rapid eye movement or REM sleep, which occurs about every 90 to 110 minutes of your sleep, with predominantly slow-wave sleep taking place in the first half of the night, and REM in the second half.
During your sleep, the hypothalamus in your brain secretes corticotropin-releasing hormone (CRH), which binds with the CRH receptors in your anterior pituitary gland, releasing adrenocorticotropic hormone (ACTH). ACTH interacts with the adrenal cortex, producing cortisol. Cortisol levels begin to rise within 2 to 3 hours of sleep and continue to elevate during early morning and waking hours.
Cortisol levels generally fall by bedtime and increase during the night – reaching their peak just before you wake up. This acts as a wake-up signal, increasing your appetite and energy. Sleep is a complex phenomenon that involves multiple hormones to maintain our body and health.
Here’s a summary of some of the hormones released during our sleep, and how they help the body:
- Growth Hormone: For growth and tissue repair.
- Melatonin: Releases with increased darkness, and signals the body to sleep.
- Oxytocin: Peaks after 5 hours of sleep and may influence your dreams.
- Cortisol: Involved in immune response, metabolism, and stress response. Levels rise before waking up to increase hunger and wakefulness in the morning.
When Does Cortisol Become a Problem?
Throughout your sleep cycle, your body releases cortisol in different amplitudes. When your body is stressed, such as during a fasted state, the high levels of cortisol decrease your restorative slow-wave sleep and increases light sleep. A common complaint among intermittent fasters is they frequently wake in the night. In this scenario, your elevated cortisol levels may be to blame.
Your body produces more cortisol when you’re stressed, when your blood sugar levels are low, when you stub your toe or when you have too much caffeine. During fasting, when the body is pumping out high levels of cortisol, the brain cannot tell whether our blood sugar levels are low, or whether we are in a threatening situation. The brain cannot tell the difference between low blood sugar and a potential threat. Therefore, it stimulates a stress response.
When the body releases too much cortisol, it will eventually lead to the production of increased adrenaline, resulting in increased wakefulness. However, as the body produces increased amounts of adrenaline, it also sets you up for a quick burnout, thus resulting in adrenal fatigue and exhaustion. Over time, this cortisol load can cause these health issues:
- Increased stress and anxiety
- Increased belly fat
- Hormonal imbalances
- Insulin resistance
- Type-2 diabetes
- Cardiovascular disease
- Weight gain
- Thyroid issues
- Digestive issues
- Chronic fatigue
- Weakened immune system
- Fertility issues
- Sleep problems, such as insomnia
During fasting, your body releases a neurotransmitter called orexin, also called hypocretin. Orexin keeps you alert, increases body temperature, makes you want to eat, and elevates your metabolism. According to a study conducted by the University of Liverpool, low orexin levels in mice are linked to obesity – even when fewer calories are taken than usual.
Restricting your food intake activates hypocretin cells. Also, anything that stimulates the release of cortisol, such as reduced sleep, will further boost the release of orexin. This seriously fires your appetite putting you in a vicious cycle. When you have high levels of orexin in your body due to intermittent fasting, you’ll have difficulty going to sleep. This is because the neurotransmitter increases alertness and wakefulness.
Furthermore, orexin also expresses leptin receptors. Studies show that injecting mice with leptin (appetite-regulating hormone), decreases their orexin activity. This shows that orexin is stimulated partly by declining leptin levels in the blood, and an increase in leptin, reduces the activation of orexin. According to experiments, re-feeding brings orexin levels back to normal to a certain extent.
What’s the Role of Leptin in Sleep and Obesity?
The less you sleep, the lower your leptin levels. Leptin is an appetite-suppressing hormone; therefore, lower levels may cause you to graze more, increasing your risk of gaining weight. Furthermore, orexin stimulates your appetite and wakefulness and is activated through the increasing release of cortisol, which in this case, is from fasting.
The only way to feel tired and go to sleep is to lower your orexin levels, by re-feeding. Sounds great, but this may not necessarily work for everyone, especially if their bodies are leptin resistant. Having leptin resistance means that your body isn’t able to completely utilize rising levels of leptin after eating again following a fast.
People who may be leptin resistant and may not respond to re-feeding, include:
- Someone who is stressed
- Someone currently coming out of a yo-yo dieting system or severe caloric restriction
- Someone with a history of insomnia
- Someone with an over-stimulated appetite
- Underweight individuals, due to their low leptin levels
- Someone with an eating disorder, such as binge eating disorder or bulimia
- Someone with adrenal fatigue
Understanding Leptin Sensitivity
Your body has a “Stop eating” hormone called leptin that plays a major role in regulating your hunger and weight. Leptin sends signals to the brain when your energy needs have been met during a meal while controlling your energy expenditure. A well-functioning leptin system results in improved brain function, performance, memory, mental sharpness, and mood.
However, not taking care of your leptin levels can bite you in the back, causing leptin resistance. Luckily, this can be reversed with appropriate diet and lifestyle modifications.
But first, let’s understand what causes leptin resistance in the first place.
What Causes Leptin Resistance?
Many diets claim that consuming fewer calories and less fat or carbs are surefire ways of losing weight. However, this strategy doesn’t last too long. With time, your caloric restrictions lower your leptin levels, slowing down your metabolism and making it increasingly difficult for you to lose excess pounds.
Note that leptin imbalances can occur when you ignore its “stop eating” signals as well. Leptin is the hormone that lets you know when you’re full; continuing eating in the long-term despite feeling full can set you up for leptin resistance. Overeating negatively affects your body’s ability to determine whether your fat levels are too high. What’s worse is that constantly ignoring your leptin signals can also cause the leptin receptors in your brain to become numb, preventing you from feeling full in the future.
Leptin resistance is also a red flag for insulin resistance as leptin plays a critical role in monitoring insulin sensitivity. According to a study published in Obesity Research, insulin sensitivity alone can contribute to obesity and type-2 diabetes. Researchers also believe that frequent exposure to stressors and toxins can increase your risk of leptin resistance.
How to Improve Leptin Sensitivity
Short-term fasting can drop your leptin levels. If you feel your leptin sensitivity can use some TLC, try the following tips:
- Cut back on refined and processed foods
- Have a breakfast rich in protein and good fats to promote healthy hormone production
- Reduce your intake of refined carbs, such as white flour and sugar
- Finish eating 4 to 5 hours before you sleep
- Consume a diet rich in fiber and protein. This will eliminate food cravings and give your hormones and liver some good rest. Furthermore, late-night snacking affects your biological clock that works alongside leptin levels.
- Increase your intake of anti-inflammatory omega-3 fatty acids. You can get omega-3s from avocado, fish and nuts, and seeds. You’d also want to limit your intake of pro-inflammatory omega-6, from processed and refined vegetable oils, processed food, and conventional meat. Omega 3s reduce stress and thereby, improve leptin performance
How to Improve Sleep While Fasting
The stress associated with fasting can make your brain more alert. From an evolutionary perspective, our cavemen ancestors would have to stay alert for any hunting opportunities. However, in the modern-day, the wakefulness that results from intermittent fasting can keep us from falling asleep during the night.
Like most negative effects of fasting, insomnia is worse during the first few days of fasting and improves as you continue intermittent fasting for several days. However, for some people, insomnia remains an issue during fasting.
If you’re having a hard time falling asleep on fast days, the following expert-approved strategies are sure to help.
Save Some Calories for Before Bedtime
Ideally, you shouldn’t be eating right before bedtime, especially during intermittent fasting. However, if you are having trouble falling asleep, consuming high protein or high-fat snacks, such as yogurt, warm milk, or a cube of cheese, can help.
Therefore, if you’re counting calories, be sure to allow some for a late-night snack.
Maintain Good Sleep Hygiene
Sleep hygiene means taking the right steps to prepare for sleep. Some examples of good sleep hygiene practices include:
- Avoid Looking at a Screen Close to Bedtime. This means turning off your television, shutting down your computer, and avoiding using your tablet, cell phone, or any other smart device. These devices release artificial blue light that inhibits the production of melatonin – a sleep hormone that responds to light and dark.
- Keep Your Bedroom Cool and Dark. Our bodies are designed to sleep during the night. Therefore, we release more melatonin when it is cool and dark.
- Reserve Your Bedroom for Sleep and Sex Only. Do not use your bedroom for screen-based entertainment, work, hobbies, or anything that requires you to be mentally active. This helps send positive signals to your brain that it is time to sleep as soon as you enter your bedroom.
- Avoid Working Out Close to Bedtime. This can increase your alertness and stress even further and prevent you from falling asleep. Your best option is getting exercise in the daytime to create a healthy level of fatigue when you reach bedtime.
- Avoid Sleeping in Late in the Morning. Instead of trying to take naps and sleeping in extra to make up for lost sleep in the night, have a set sleep schedule. For example, sleep at 11 pm and wake up at 7 am. This prevents any confusion for your biological clock.
- Invest in Comfortable Bedding. And always make your bed as soon as you get up. A bed that is made is more inviting versus an unmade bed which can trigger stress and reduces feelings of relaxation.
Get Some Sun in the Morning
Constantly staying in low light indoors can seriously impact your circadian rhythm and the hormones that regulate sleep. Even a brightly lit room is no match for the natural brightness of the sun. Getting up and leaving the house for some sun can help maintain your biological clock and promote better sleep.
Furthermore, sun exposure promotes the production of vitamin D in the body, which plays a role in numerous bodily processes – including sleep.
As a bonus, a study conducted by Northwestern University, Chicago, Illinois shows that individuals who spend more time outdoors during early morning hours generally tend to weigh less.
Take the Right Supplements
Some effective sleep supplements include magnesium and melatonin. Magnesium deficiency is common, and the mineral plays a crucial role in regulating sleep. Some forms of magnesium are better absorbed than others. For insomnia, magnesium citrate is recommended.
Taking melatonin on days when you’re fasting can also help you get better sleep and reestablish your sleep patterns. Melatonin is a sleep hormone that is naturally produced in the body to support sleep.
Don’t shy away from smaller doses such as 0.5 mg. You can increase your dosage slowly if a lower dose doesn’t work for you. Work your way up to 3 to 5 mg, if needed but understand that taking more may not necessarily help you fall asleep faster. Less is more when it comes to taking melatonin supplements.
Consume More Tryptophan- Containing Foods
Ever wondered why turkey dinners could be so comforting? This is because turkey is packed with tryptophan, an amino acid that promotes serotonin and melatonin production. Foods containing tryptophan include poultry, eggs, cheese, pumpkin seeds, sesame seeds, mung beans, and kidney beans.
Get Off the Blood Glucose Rollercoaster
Following a heavy meal, your blood sugar levels spike rapidly. This stimulates the release of insulin to bring blood glucose levels back to normal. However, most of the time, the increased surge of insulin causes blood sugar to drop lower than normal, resulting in an energy crash and increased cravings for sugar.
If hunger and increased cravings are keeping you awake, try avoiding blood glucose fluctuations throughout the day. To do this, avoid adding too many sugars, artificial sweeteners, and refined carbs to your meals. Stay away from high glycemic foods and increase your intake of filling protein, good fats, and fiber. In case you are craving something sweet, adding some protein or good fat to it will lower its glycemic value and increase your satiety faster.
Stop Drinking Coffee After Midday
Caffeine lasts in your system for up to 8 hours, countering the effects of melatonin. To avoid caffeine from keeping you up in the night, stop drinking high-caffeine beverages after 12:00 noon. If you’re looking for a quick boost, try a caffeine-free alternative such as cold coconut water, a cool cold-pressed juice, or just getting some sunlight.
Take Shorter Naps
The sleep deprivation that occurs during fasting stages in the night may increase your urge to nap more in the daytime. However, taking long, frequent naps can throw your natural circadian rhythm out of whack, causing you to lie wide awake when it’s bedtime.
The solution: Take one short nap. Have a set nap time for any day you feel the need for a quick energy boost. Our alertness usually dips between 1 pm to 3 pm, so set your naps for this time of the day.
Furthermore, keep your naps super short: 10 to 15 minutes is enough to get some energizing light sleep. When you sleep for longer than 20 minutes, you enter deeper stages of your sleep. Waking up out of deep sleep can leave you feeling groggy and lethargic and hence, is not recommended when you’re looking to increase your energy.
Understand that intermittent fasting alone will not solve your body weight, blood sugar, or inflammatory issues. Not taking the correct steps to improve your sleep and optimize your fasting can prevent you from enjoying the benefits of this favorite eating style. You have to practice proper sleep techniques while incorporating measures to keep your leptin sensitivity in check. Allow your body to rest, and include plenty of high-quality protein and good fats, from fish, avocado, olive oil, and nuts to promote the healthy production of sleep-promoting hormones.
Here are some practical ways to give yourself more energy on 4 hours of sleep.