It’s likely that our ancestors, who lived hunter-gatherer lifestyles, fasted out of necessity. They may have gone for days at a time without food due to lack of resources, and feasted only when the opportunity presented itself. With the introduction of agriculture and the rise of modern-day society, fasting has become less common. Especially when food (often the unhealthy, processed variety) is so readily available and celebrated—feasting is much more prevalent than fasting. But, in recent years, fasting has seen a resurgence as a way to reset the body and get back on track with healthier eating habits. Most people are familiar with intermittent fasting (IF), where you alternate between periods of eating and not eating for at least 12-14 hours. Dry fasting (DF) is in the advanced level of the fasting scale, and involves going without both food and water for an extended period of time—from 16 hours up to several days.
However, dry fasting is not for everyone. In fact, it isn’t recommended for those who are new to fasting, as it’s a much more intense version of the practice and can be difficult to stick with. In this article, we explore everything you need to know about DF. Is it evidence-based? Are the purported benefits legit? What precautions should you take when considering DF? Let’s find out!
Putting The “Dry” In Dry Fasting
What makes dry fasting different from other forms of fasting? Well, it’s all in the name—going without not just food but also water for an extended period of time. But, water is life, right? We need it to survive. How can our bodies cope without it for long periods of time?
Turns out, our bodies are surprisingly resilient and capable of adapting to this stressor. Just like when you practice IF, a process called autophagy (where old, damaged cells are recycled and replaced with new ones) is activated (23). In the absence of food, your body begins to scavenge for energy from stored fat, which it then uses to maintain homeostasis (5).
Additionally, due to the lack of water intake, toxins that are stored in the body’s fatty tissue are released and filtered out through your kidneys, leaving you feeling lighter and healthier.
But in dry fasting, the process goes one step further as it puts more stress on the body due to going without water for an extended period of time.
At the cellular level, it’s theorized that a different process occurs during DF. It’s all about exogenous vs endogenous water—the difference between external and internal sources of water.
When you practice IF, your body is still getting some water from your food and drinks, so it’s considered exogenous hydration. But with DF, all external sources of water are removed, forcing your cells to rely solely on their own endogenous (internal) stores of water. It’s thought that this helps to detoxify the cells and reduce inflammation.
Think about it—you have strong healthy cells, some old and weak, others sick, and also some bacteria, viruses, and fungi. When a “survival for the fittest” situation is created by the dry fast, weak and sick cells are destroyed and the stronger ones survive.
Bacteria, viruses, and fungi may not thrive in this environment either. This leaves you with a healthier body overall. It’s like hitting the reset button!
It’s important to note that most of the benefits associated with dry fasting are largely based on anecdotal evidence—there just isn’t enough research out there yet to make any definitive conclusions.
So, if you’re considering DF, it’s important to do your own research and consult with a health professional before proceeding.
Is There Any Evidence For Dry Fasting?
When it comes to DF, there just isn’t much research out there—which makes sense since it’s not a widely practiced form of fasting. Plus, it’s dangerous to conduct studies on something that could potentially have deleterious effects on the participants.
That said, there are some promising studies based on Ramadan fasting, which is similar to DF. During Ramadan (the holy month in the Muslim faith) Muslims are expected to fast from dawn till dusk, during which time they cannot eat or drink.
The findings of such studies are limited because at dusk, participants are allowed to eat and drink, so the full effects of DF aren’t realized.
A few studies on mice offer insight into the potential benefits of dry fasting (2) (7). While the results of these studies can’t be directly translated to humans, they do suggest that DF could have some positive effects.
More evidence in support of DF is often obtained from studies on IF.
Theoretically, some similarities can be drawn between DF and IF, since both put stress on the body due to going without food or water for an extended period of time. However, it’s important to note that these two forms of fasting are very different and shouldn’t be seen as interchangeable.
Finally, anecdotal evidence also exists to support the potential benefits of DF. People who practice this form of fasting often report feeling positive effects, and this may encourage others to give DF a try.
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Why Is Dry Fasting So Good?
Proponents of DF often cite a wide range of potential benefits, and we’ll review each one to help you decide if it’s something you want to try.
You’ll Shed Pounds
This is the most commonly cited benefit, and also the most obvious. When you don’t eat or drink anything for a significant period of time, your body begins to burn through the stored energy it has.
Over the course of several days, this can result in significant weight loss. Whether the weight loss is permanent or not is a bit of a toss-up, however.
Long-term, sustainable weight loss requires a combination of healthy diet and exercise (15). You’ll need to unlearn any bad habits that have led to weight gain, and DF won’t help with this. Not to mention that extreme calorie restriction is known to backfire.
Your body may become confused and slow its metabolism, leading to weight gain when you do start to eat again. Furthermore, deprivation can lead to unhealthy binges, furthering the cycle and sabotaging your goals.
Some research supports the notion that DF can help with weight loss. In a study of the effects of Ramadan fasting on weight, for instance, researchers found that participants lost weight and had a lower BMI after 19 days of abstaining from food and water during the day (16).
However, it’s important to note that these participants fasted intermittently (didn’t for more than 24 hours) and were allowed to eat at night. In addition, the fast was limited to one month, so the longevity of any weight loss isn’t certain.
Your Inflammation Markers May Drop
It’s been suggested that DF may help reduce inflammation throughout the body. However, the evidence supporting this is sparse.
Supporters rely on the well-documented anti-inflammatory effects of IF and the similarity between the two forms of fasting, but the connection hasn’t been studied directly.
IF can decrease inflammation by reducing levels of certain chemicals that contribute to inflammation and oxidative stress, such as cytokines and leukotrienes (13).
IF also increases anti-inflammatory compounds in the body such as endorphins and growth hormones, which have been found to reduce inflammation. And lastly, IF stimulates autophagy, a process that eliminates damaged cells and reduces systemic inflammation (11).
It’s unclear whether DF can have similar effects as IF, but some people believe that it can.
A study of healthy adults during the month of Ramadan, for instance, found a significant reduction in C-reactive protein (CRP), an inflammatory marker after 3 weeks of fasting. However, again, keep in mind that participants didn’t fast for more than 24 hours at a time and were able to eat during the night (18).
More research is needed to confirm the potential anti-inflammatory benefits of DF, but it may be something to keep in mind if you’re looking for ways to reduce inflammation.
Your Immunity May Be Boosted
Immune functioning is also thought to be improved by DF. Again, it’s difficult to draw a direct link as the two forms of fasting haven’t been studied side-by-side. However, we can look to IF and the potential benefits it may have on immunity.
IF has been found to reduce inflammation, as we discussed above. This in turn can improve immune functioning, since inflammation is known to impair the functioning of the immune system (19). It’s possible that DF could have similar benefits in this regard.
You Might Age Slower
Aging is a complex process and one of the major factors in determining how quickly you age is your telomeres.
Telomeres are the protective caps at the end of our chromosomes that shorten as we age. As they get shorter, our cells become less efficient and die faster, which leads to the various signs of aging (Skin wrinkles, graying hair, cell damage) (20).
Fasting has been found to protect telomeres, likely due to its anti-inflammatory effects (8). It’s unclear whether DF has similar effects, but some people believe that it can help slow the aging process too.
In fact, healthier skin is one of the most widely reported benefits of DF (6). People who practice it regularly often report smoother, brighter skin with fewer blemishes and wrinkles. This could be due to the anti-inflammatory and antioxidant effects of DF, though more research is needed to confirm this connection.
You May Be More Alert And Focused
People often cite increased mental clarity and focus when they practice DF. Research shows that fasting increases the production of a neurotransmitter known as orexin-A, that increases alertness (24).
Others point to the fact that IF increases levels of brain-derived neurotrophic factor (BDNF), which has been linked to improved memory, learning, and focus (12).
While there’s no direct evidence to support the claim that DF can improve mental clarity, it’s plausible that similar effects may occur. It’s important to note, though, that extreme fasting can have a negative impact on cognitive functioning, so it’s best to practice moderation.
You’ll Feel More Spiritually Grounded
Lastly, many people who practice DF report that it helps them become more spiritually connected and grounded. This could be due to the fact that it encourages mindfulness and introspection.
It’s also possible that DF improves spiritual connection by helping people to slow down and take a break from the hustle and bustle of life.
When we’re constantly on the go, it’s easy to lose track of our spiritual selves. But when we take time to practice DF, we’re forced to turn inwards and reconnect with our true selves.
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You Might Feel Less Hungry
Perhaps the most controversial potential benefit of DF is the claim that it can reduce hunger levels. On one hand, we know that drinking water can help reduce appetite and signal to the body that it’s full, so this claim might be far-fetched (3).
Surely, fasting for an extended period of time without water would only make you hungrier, right?
Surprisingly, some people report that they feel less hungry while engaging in DF (9). This could be due to the fact that no energy is being expended on digestion, allowing the body to conserve energy.
Though not scientific in nature, it could be possible that DF could lead to reduced hunger levels in some cases.
There’s a mental aspect to hunger as well. People who practice DF often report that they feel more in control of their cravings, which can lead to a better relationship with food.
Why Should You Be Wary Of Dry Fasting?
Despite the potential benefits of DF, it’s important to be cautious about this practice. It’s not without its side effects and in some cases can actually be detrimental to your health and wellbeing.
It Has Unpleasant Side Effects
Like other types of fasting, DF can make you physically and mentally uncomfortable. You may experience:
- Extreme hunger pangs – Dry fasting deprives the body of much-needed nutrients and hydration, both of which can lead to severe hunger pangs.
- Headache – Dehydration is one of the most common side effects of DF, which can cause headaches and dizziness (1).
- Mood swings – Abstaining from food and water can take a toll on your emotional wellbeing, leading to mood swings (22).
- Exhaustion – Without food and water, your body can become severely weakened, leading to feelings of exhaustion (22).
- Decreased urination – DF can lead to a decrease in urination as the body conserves water.
You’re At Risk Of Dehydration
The most serious risk associated with DF is dehydration. When the body doesn’t get enough water, it begins to shut down certain systems and organs as a way to conserve it. This can lead to extreme weakness, dizziness, fainting, and even death if not treated immediately (1).
You Might Develop Urinary Tract Infections
Another potential risk of DF is urinary tract infections. When you don’t drink enough water, your body begins to produce concentrated urine, which can lead to irritation in the bladder and urinary tract.
This irritation can cause painful burning sensations when urinating and an increased risk of infection (17).
You Might Experience Nutrient Deficiencies
Continuous DF can lead to nutrient deficiencies, as the body isn’t getting any of the necessary vitamins and minerals it needs to function properly. This can cause a variety of health issues, including fatigue, weakness, anemia, and even organ failure (14).
You Might Trigger Disordered Eating
People who engage in DF may begin to view it as a way to lose weight or control their portion sizes, which can lead to more serious issues. It’s important to remember that DF is not an appropriate way to diet and should never be used as such.
Who Shouldn’t Practice Dry Fasting?
Though some people may choose to practice DF as a spiritual or health-related endeavor, there are certain individuals who should avoid this practice altogether. These include:
- Children and adolescents
- Pregnant women
- People with pre-existing medical conditions
- People who are underweight
- People with diabetes
- People taking medications that require food or water intake
- People who are prone to disordered eating
- People with a history of eating disorders
Ultimately, it’s important to understand the potential risks and rewards of DF before engaging in this practice. Talk with your doctor if you’re considering trying dry fasting to make sure it’s the right decision for you.
DF can have potential benefits, but it’s important to be aware of the risks associated with this practice. Before attempting DF, consult with your doctor to determine if it’s safe for you.
This article is intended for general informational purposes only and does not address individual circumstances. It is not a substitute for professional advice or help and should not be relied on to make decisions of any kind. Any action you take upon the information presented in this article is strictly at your own risk and responsibility!
- Adult Dehydration (2022, ncbi.nlm.nih.gov)
- Differential adaptive responses to 1- or 2-day fasting in various mouse tissues revealed by quantitative PCR analysis (2015, sciencedirect.com)
- Effect of Pre-meal Water Consumption on Energy Intake and Satiety in Non-obese Young Adults (2018, ncbi.nlm.nih.gov)
- Effects of Daytime Dry Fasting on Hydration, Glucose Metabolism and Circadian Phase: A Prospective Exploratory Cohort Study in Bahá’í Volunteers (2021, frontiersin.org)
- Energy metabolism in feasting and fasting (1979, pubmed.ncbi.nlm.nih.gov)
- Fasting and Its Impact on Skin Anatomy, Physiology, and Physiopathology: A Comprehensive Review of the Literature (2019, mdpi.com)
- Fasting drives the metabolic, molecular, and geroprotective effects of a calorie restricted diet in mice (2022, ncbi.nlm.nih.gov)
- Fasting for stem cell rejuvenation (2020, ncbi.nlm.nih.gov)
- How Experiences Affect Psychological Responses During Supervised Fasting: A Preliminary Study (2021, ncbi.nlm.nih.gov)
- Impact of fasting on food craving, mood and consumption in bulimia nervosa and healthy women participants (2012, pubmed.ncbi.nlm.nih.gov)
- Intermittent and periodic fasting, longevity and disease (2021, ncbi.nlm.nih.gov)
- Intermittent fasting and cognitive performance – Targeting BDNF as potential strategy to optimise brain health (2022, sciencedirect.com)
- Intermittent fasting during Ramadan attenuates proinflammatory cytokines and immune cells in healthy subjects (2012, sciencedirect.com)
- Main nutritional deficiencies (2022, ncbi.nlm.nih.gov)
- Maintenance of lost weight and long-term management of obesity (2018, ncbi.nlm.nih.gov)
- Metabolic Response to Daytime Dry Fasting in Bahá’í Volunteers—Results of a Preliminary Study (2022, ncbi.nlm.nih.gov)
- PURLs: Can drinking more water prevent urinary tract infections? (2020, ncbi.nlm.nih.gov)
- Ramadan Fasting Exerts Immunomodulatory Effects: Insights from a Systematic Review (2017, frontiersin.org)
- Role of Intermittent Fasting on Improving Health and Reducing Diseases (2014, ncbi.nlm.nih.gov)
- Telomeres and Aging (2008, journals.physiology.org)
- The Complicated Relationship between Dieting, Dietary Restraint, Caloric Restriction, and Eating Disorders: Is a Shift in Public Health Messaging Warranted? (2022, mdpi.com)
- The Effect of Fasting on Human Metabolism and Psychological Health (2022, ncbi.nlm.nih.gov)
- The effect of fasting or calorie restriction on autophagy induction: A review of the literature (2018, sciencedirect.com)
- The effects of diurnal intermittent fasting on the wake-promoting neurotransmitter orexin-A (2018, ncbi.nlm.nih.gov)