Dry Fasting: Benefits, Risks, Types and How to Do It

Dry fasting, or absolute fasting, is among the diet approaches that have gained recent attention for their unique restrictions and purported advantages.

If you plan on stepping up your diet regimen and want to know if dry fasting is for you, then you’re on the right page. This scientifically detailed article will explore the types, benefits, risks, and specific instructions on implementing dry fasting.

Key Takeaways:

  • Dry fasting means complete abstinence from food and liquids.
  • It reduces inflammation, delays aging, and improves weight loss, immune function, and skin health.
  • Dry fasting can cause headaches, fatigue, irritability, and dehydration.
  • While soft dry fasting allows contact with water, hard dry fasting does not.

Table of Contents:

What Is Dry Fasting?

Dry fasting is an intensive form that involves complete abstinence from food and liquids, setting it apart from other fasting methods.

Unlike traditional fasting, which often encourages water intake, dry fasting takes a more stringent approach, prohibiting any form of hydration.

Dry Fasting Methods

  1. Intermittent Dry Fasting – Like regular intermittent fasting, you should restrict food for a certain number of hours, mostly 16/8, and avoid water and food during fasting. Muslims also practice this during Ramadan, known as the dawn-to-dusk fast.
  2. Alternate-Day Dry Fasting – This method restricts food and water every other day.
  3. Periodic Dry Fasting – Some people do it for more extended periods with less frequency. For instance, some may do a 3-5 day dry fasting once or twice a year.

Types of Dry Fasting

dry fasting

Soft Dry Fast

Individuals participating in a soft dry fast refrain from eating water or other fluids but allow some activities requiring contact with water, including brushing teeth, cleaning the face, and bathing. While less intense, this dry fasting adheres to the essential premise of refraining from liquid consumption.

Soft dry fasting supporters say that the advantages of fasting remain intact despite coming in contact with water. However, detractors argue that the potential of unintended water intake during such activities might jeopardize the dry fast’s cleanliness.

Hard Dry Fast

A hard dry fast imposes a more rigorous set of rules, prohibiting contact with water, even for routine personal hygiene practices like brushing teeth or bathing.

This dry fast adheres strictly to abstinence from food and liquid, pushing the body to rely solely on internal reserves for sustenance.

While a hard dry fast is considered more challenging and potentially uncomfortable, proponents argue that it may yield more profound benefits due to the heightened physiological stress and reliance on stored resources.

However, most consider this to be one of the strictest fasts, and beginners should make a lot of considerations before getting into this.

Benefits of Dry Fasting

Before diving in, note that individual results vary, and it’s vital to note your tolerance when doing dry fasting.

Weight Loss

One of the primary reasons individuals explore dry fasting is its purported effectiveness in weight loss. Studies, such as those conducted during the Bahá’í fasting,1 indicate that intermittent dry fasting can reduce body weight, body mass index, body fat, and blood glucose.

The same study also suggests improved insulin sensitivity and increased fat burning.

However, part of the weight loss observed during dry fasting is also due to water weight loss.

Improved Immune Function

Supporters of the fasting mehtod claim that it can enhance the body’s immune function by triggering a process known as autophagy.2 Autophagy is the body’s natural mechanism for removing damaged or dysfunctional cells and promoting the regeneration of new, healthier cells.

Delayed Aging and Skin Benefits

While others may think that dry fasting causes skin dehydration, supporters claim not to experience any difference. Studies show that people with certain skin conditions benefit from fasting,3 and intermittent fasting improves wound injury healing.4

Reduced Inflammation

Chronic inflammation is associated with various health conditions, including heart disease, arthritis, and diabetes. Studies conducted during fasting have shown lower proinflammatory cytokines, indicating a potential anti-inflammatory effect5, and another study shows that dawn-to-dusk fasting induces anti-inflammatory effects.6

Holistic Improvements

While results highly vary, proponents of the method often claim holistic improvements in well-being. These may include increased mental clarity, heightened spiritual awareness, and a sense of overall rejuvenation.

Dry Fasting Side Effects

Hunger Pangs and Fatigue

As with any fasting method, it may induce hunger pangs and fatigue. This often comes with a dry mouth and increased thirst.

Headaches and Poor Focus

Restricting caffeine and nutrients, especially carbohydrates, during dry fasting may contribute to headaches and poor focus.

We also know these side effects as keto flu.


The physiological stress of dry fasting may lead to mood-related side effects, including mood swings and irritability. These mood changes can be attributed to hormonal fluctuations and the body’s response to the perceived stress of fasting.

Decreased Urine Output

You will likely experience increased urination during the initial phase, decreasing as you lose more water. You will also notice a darkening of your urine color.

Potential Risks of Dry Fasting

Dehydration and Kidney Problems

Continued dry fasting may cause dehydration, leading to electrolyte imbalances and hypotension, which can be fatal.7 Chronic dehydration may lead to urinary tract infections (UTIs) and the formation of kidney stones.8

Malnourishment and Eating Disorders

Prolonged dry fasting can result in macronutrients and micronutrients, leading to malnourishment. Some also binge eat after the fasting period, which may increase risks for eating disorders.


Hypoglycemia happens when the body lacks glucose to maintain body functions. Symptoms include headache, dizziness, anxiety, nervousness, and shaking.

When the body goes into ketosis, most of these symptoms disappear again.

Specific Instructions To Follow

Dry fasting is not for everyone. Please take note of the following considerations:

  1. Dry fasting is not recommended for individuals with pre-existing medical conditions or eating disorders. Healthy individuals should seek advice from health experts before starting. Individuals with existing stress, depression, or other health issues should avoid it.
  2. Those with kidney problems, high blood pressure, or blood sugar fluctuations should only undertake dry fasting under proper guidance.
  3. Dehydration should be closely monitored; water is the safest to have first when breaking the fast.
  4. Fasting frequency should be determined based on individual health status and needs. It is not a one-size-fits-all approach.
  5. Proper meal planning and scheduling are crucial during this extreme fasting method.


This fasting regimen affects individuals differently, and despite some reported benefits, the lack of comprehensive scientific evidence raises concerns.

Considering the potential risks and uncertainties, it is crucial to approach dry fasting cautiously and, ideally, under the supervision of healthcare professionals.

Frequently Asked Questions (FAQ)

How long can you do dry fasting?

Beginners can start by doing a 12-16 hour dry fast first and then do an alternative day dry fast or periodic dry fast for a few days after getting accustomed to it.

Are dry fasts healthy?

While there are recorded benefits, there is no evidence of safety for long-term approaches. Consulting your healthcare provider is necessary.

What do you eat during dry fasting?

Dry fasting involves complete abstinence from both food and liquids. No water, broth, tea, or fluid is allowed during fasting.

How long can a human being dry fast?

Some enthusiasts claim to remain fine after 3-5 days, but the maximum safe duration for dry fasting is not well-established.


1Mähler, A., Jahn, C., Klug, L., Klatte, C., Michalsen, A., Koppold-Liebscher, D., & Boschmann, M. (2022). Metabolic Response to Daytime Dry Fasting in Bahá’í Volunteers—Results of a Preliminary Study. Nutrients, 14(1). https://doi.org/10.3390/nu14010148

2Bagherniya, M., Butler, A. E., Barreto, G. E., & Sahebkar, A. (2018). The effect of fasting or calorie restriction on autophagy induction: A review of the literature. Ageing research reviews, 47, 183–197. https://doi.org/10.1016/j.arr.2018.08.004

3Mansilla-Polo, M., Piquero-Casals, J., & Morgado-Carrasco, D. (2023). Popular Diets and Skin Effects: A Narrative Review. “Dietas populares y su impacto en la piel. Una revisión narrativa”. Actas dermo-sifiliograficas, S0001-7310(23)00846-3. Advance online publication. https://doi.org/10.1016/j.ad.2023.10.015

4Luo MJ, Rao SS, Tan YJ, Yin H, Hu XK, Zhang Y, Liu YW, Yue T, Chen LJ, Li L, Huang YR, Qian YX, Liu ZZ, Cao J, Wang ZX, Luo ZW, Wang YY, Xia K, Tang SY, Chen CY, Xie H. Fasting before or after wound injury accelerates wound healing through the activation of pro-angiogenic SMOC1 and SCG2. Theranostics. 2020 Feb 19;10(8):3779-3792. doi: 10.7150/thno.44115. PMID: 32206122; PMCID: PMC7069085.

5Lavin DN, Joesting JJ, Chiu GS, Moon ML, Meng J, Dilger RN, Freund GG. Fasting induces an anti-inflammatory effect on the neuroimmune system which a high-fat diet prevents. Obesity (Silver Spring). 2011 Aug;19(8):1586-94. doi: 10.1038/oby.2011.73. Epub 2011 Apr 28. PMID: 21527899; PMCID: PMC3695639.

6Mindikoglu AL, Park J, Opekun AR, Abdulsada MM, Wilhelm ZR, Jalal PK, Devaraj S, Jung SY. Dawn-to-dusk dry fasting induces anti-atherosclerotic, anti-inflammatory, and anti-tumorigenic proteome in peripheral blood mononuclear cells in subjects with metabolic syndrome. Metabol Open. 2022 Nov 1;16:100214. doi: 10.1016/j.metop.2022.100214. PMID: 36506940; PMCID: PMC9731888.

7Watso JC, Farquhar WB. Hydration Status and Cardiovascular Function. Nutrients. 2019 Aug 11;11(8):1866. doi: 10.3390/nu11081866. PMID: 31405195; PMCID: PMC6723555.

8Peerapen P, Thongboonkerd V. Kidney Stone Prevention. Adv Nutr. 2023 May;14(3):555-569. doi: 10.1016/j.advnut.2023.03.002. Epub 2023 Mar 9. PMID: 36906146; PMCID: PMC10201681.

Mag. Stephan Lederer, MSc.

Mag. Stephan Lederer, MSc. is an author and blogger from Austria who writes in-depth content about health and nutrition. His book series on Interval Fasting landed #1 on the bestseller list in the German Amazon marketplace in 15 categories.

Stephan is a true man of science, having earned multiple diplomas and master's degrees in various fields. He has made it his mission to bridge the gap between conventional wisdom and scientific knowledge. He precisely reviews the content and sources of this blog for currency and accuracy.

Click on the links above to visit his author and about me pages.

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