Fasting, a research-backed strategy to improve your health, comes in different shapes and forms. One of them is “dry fasting” in which a person doesn’t just abstain from food, but also liquid. This may seem more difficult than your usual intermittent fast — however, it comes with health benefits for those interested.
This guide cuts through the noise to explain what dry fasting entails, how it could help you, its potential risks, and how to dry fast safely.
Dry fasting, also called absolute fasting, is exactly what it sounds like: It means that you fast without consuming any form of liquid. This includes water, coffee, tea, and other calorie-free drinks.
People who hear about dry fasting are usually concerned about the possibility of becoming dehydrated, and rightfully so. It’s not for beginners and may not be the best approach for certain individuals who are at risk — for instance, athletes and active individuals.
Meanwhile, dry fasting can be safely implemented and is unlikely to have any side effects among those who are:
- Generally healthy
- Fasting only for short periods
Dry fasting is comparable to Ramadan, a special time of the year for Muslims, in which they fast from dawn to sunset without food and water (*).
Since dry fasting requires that you abstain from liquid (aside from food), it can be implemented within any type of intermittent fasting.
It won’t matter if you’ll be doing spontaneous meal skipping, the 16:8 fast, alternate-day fasting, one meal a day, or a shorter 12-hour fast. On dry fasting, you can implement any of these with the additional rule of making sure you don’t drink anything.
How long can you dry fast? You might ask. The short answer is that it depends on how long you’re able to go without liquids. In other words, you can aim for a minimum of 12 hours if you feel fine.
Keep in mind that fasting, in and of itself, causes the depletion of glycogen in your liver. As your body enters a metabolic state of ketosis, you may find yourself urinating more often. This could lead to dehydration unless you replenish with water and electrolytes.
There are two main ways to perform a dry fast — soft dry fasting and hard dry fasting. Here’s how they differ:
Soft dry fast
While you’re not allowed to consume water and other fluids, you can do other things that involve coming in contact with water. For example, brushing your teeth, washing your face, and bathing regardless of how long your fast will last.
It has been said that this type of dry fasting may increase the risk of water getting into your mouth, which defeats the purpose of dry fasting. However, the above mentioned activities allow you to feel refreshed.
Hard dry fast
On the other hand, a hard dry fast forbids coming in contact with water, even if it simply means brushing your teeth or bathing as part of your personal hygiene.
Between a soft dry fast and a hard dry fast, the former option is more comfortable for beginners on dry fasting and may be better mentally. There’s also no evidence showing that a hard dry fast is superior to a soft dry fast in terms of health benefits.
Note: Another way of categorizing dry fasting is by duration. With that being said, dry fasting can be intermittent, meaning that you do it for a small window of time each day, or prolonged, which lasts anywhere from 24 hours or more.
Like regular fasting which allows for zero-calorie drinks, dry fasting benefits are plenty. Here are some of them:
1. Reduced body weight
Many people who undergo a fast do it for weight loss reasons. Studies have found that intermittent fasting can help people lose weight and may be used as a primary approach to treat obesity (*).
However, note that the weight loss resulting from dry fasting in the short term is mostly water weight. You don’t lose fat mass overnight, but you’re likely to see a decline in total weight due to the reduced water in your system.
This is especially true because fasting itself already depletes your body’s glycogen stores, which reduces water weight (since glycogen is bound to water) — on top of the fact that you’re not drinking any more fluids during dry fasting (*).
Doing repeated fasting — whether dry fasting, water-only fasting, or fasting that includes other zero-calorie drinks — will lead to true fat loss over time.
2. Decreased inflammation
The body’s inflammatory response can either be acute or chronic. While acute inflammation is more noticeable (e.g., pain, redness, and swelling) chronic inflammation is subtle and may be caused by an autoimmune disorder, too much stress, and an unhealthy high-sugar diet.
Dry fasting has the potential to reduce and improve diseases caused by inflammation, such as diabetes, heart disease, arthritis, and bowel diseases (*).
In a 2012 cross-sectional study, healthy male and female subjects did Ramadan fasting. At the end of the third week, their proinflammatory cytokines (which are released during inflammation) were significantly lower (*).
They also had lower blood pressure, body weight, and body fat percentage.
3. Induces autophagy for anti-aging
There’s evidence that dry fasting may result in delayed aging. Fasting triggers autophagy, which is a natural process in your body that involves getting rid of damaged or dysfunctional cells (*).
Autophagic activity decreases with age, and this causes damaged cells to accumulate. Not just that, but decreased autophagy has been found to make age-related diseases worse, such as cancer and Alzheimer’s disease (*).
Through dry fasting, you can restore homeostasis and increase DNA repair. It also increases the number of your mitochondria, helping you age healthily (*).
4. Helps with insulin resistance
Another benefit of dry fasting is that it improves insulin sensitivity or the responsiveness of your cells to insulin.
A 2015 study done on healthy males who fasted during Ramadan noted a significant increase in insulin sensitivity and decreased insulin resistance after four weeks of intermittent fasting. Additionally, the subjects lost an average of 1.52 kg (*).
Boosting insulin sensitivity reduces your risk of diseases, such as prediabetes, type 2 diabetes, obesity, and heart disease (*).
5. Skin health
Dry fasting can improve your skin in different ways.
One is that reduces the likelihood of acne breakouts caused by high insulin levels (*). Another is that fasting may accelerate wound healing as it enhances endothelial angiogenesis — this describes the migration, growth, and differentiation of endothelial cells (*).
Fasting, especially when done regularly in combination with a sugar-free diet (like keto), can help reduce the appearance of wrinkles. Your diet affects your skin appearance and too much sugar damages collagen in your skin, ultimately leading to more wrinkles.
People who are new to dry fasting or any type of fasting may experience short-term side effects. Expect the following symptoms:
- Dry mouth
- Increased thirst
- Hunger pangs
- Low energy
- Inability to focus
- Mood swings
- Increased urination (but this is followed by decreased urination since you’re not drinking water until the end of the fast)
These dry fasting side effects are similar to when you’re new to the keto diet. With dry fasting, it’s usually because you’re entering ketosis combined with diminished fluid intake.
Is dry fasting safe? It depends on the person doing the dry fast since it carries risks for people who are most likely to get dehydrated.
This includes athletes, avid exercisers, people living in warmer climates, uncontrolled diabetes, older adults, and those taking medications that increase urination (e.g., blood pressure meds, diuretics, and antidepressants).
Remember that the longer the dry fast, the higher the likelihood of becoming dehydrated. Dehydration as a result of prolonged dry fasting has complications, such as low blood volume, heat stroke, seizures, kidney damage, and coma.
We recommend starting with regular fasting (where you’re allowed to drink water and other zero-calorie fluids) before jumping into dry fasting. Also, keep your dry fasts as short as possible. End your fast right away if you feel ill or experience unusual symptoms.
Reach out to a healthcare provider to discuss dry fasting before trying it, especially if you have a medical condition.
Before doing a dry fast, make sure that it’s the right option for you. Keep in mind that dry fasting isn’t optimal for everyone since there are instances where staying hydrated is absolutely necessary.
If you’re new to dry fasting, it would be a good idea to ease into it. Restrict food and water for a few hours — let’s say 4 hours — and gradually increase those hours until you feel comfortable with a full 12-hour fast. From there, you can proceed to a 16-hour fast, then a 24-hour fast.
The idea is to allow your body to adjust.
As for your pre-dry fasting meal, we recommend focusing on healthy fats, protein, and complex carbohydrates. Examples are eggs, grass-fed beef, fatty fish, cruciferous vegetables (like cauliflower and broccoli), avocados, and berries. Check out these top intermittent fasting foods for your feeding window.
Stay away from highly processed and sugary options since these will lead to blood sugar spikes, causing you to feel hungrier later on (*).
Like regular intermittent fasting, you can dry fast for 12 to 24 hours according to your level of tolerance. Remember to start slow. Here are some common dry fasting schedules:
- 16:8 – restricting food and water for 16 hours, followed by a feeding window.
- 20:4 – eating and drinking within a 4-hour window and fasting for 20 hours.
- Alternate-day fasting – fasting for 24 hours every other day.
- One meal a day – OMAD for short, this is when you fast for 23 hours and consume all your calories from food and drinks within a 1-hour eating window.
As you can see, there are plenty of ways to dry fast. Feel free to try each one, and be mindful that what works for others won’t always work for you.
There are no definitive rules on the number of times you should fast. Whether you do it once or twice a week, or a few times each month, make sure to follow a healthy diet in general.
What you eat around your fasts — pre-fasting and post-fasting meals — will fulfill your nutritional needs, influence weight loss, and reduce your risk for disease.
Break a dry fast properly with nutrient-dense, unprocessed, low-glycemic, and easy-to-digest foods.
Excellent options include bone broth, fermented foods (kimchi, sauerkraut), eggs, and fatty fish. Plan these meals ahead so that you wouldn’t end up breaking your fast with unhealthy foods. Simple carbs like white bread, pasta, and pastries are the worst foods to eat.
Practice mindful eating by chewing your food slowly and savoring it. Stop when you’re about 80% full.
And last but not least, replenish electrolytes. You can consume Perfect Keto Electrolytes or simply blend pink Himalayan salt, lemon juice, and stevia in water.
Dry fasting is not ideal for the elderly, women who are pregnant or breastfeeding, and individuals with a history of an eating disorder. Additionally, you should check with a doctor first if you have a medical condition.
Below are common questions and answers relating to dry fasting:
What’s the difference between dry fasting and water fasting?
Dry fasting restricts both food and water for an extended period, whereas water fasting (or “water-only fasting”) restricts food but allows you to consume water. Water fasting helps you reap the benefits of autophagy without the risk of becoming dehydrated.
Can you exercise while dry fasting?
While exercise isn’t forbidden on any type of fast, note that exercise makes you lose water from sweating. If you don’t replace fluids, you raise your risk of dehydration. Instead of exercising in the middle of a dry fast, consider doing it during your feeding window.
Can I eat food during dry fasting?
The only time you’re allowed to do that is at the end of a fast. Break your fast with foods and drinks full of vitamins and minerals, and that do not contain too many carbs.
Because dry fasting doesn’t allow any fluid intake, it’s not the best approach for people who haven’t tried regular water fasting previously and those who are most at risk of dehydration.
In contrast, it can be easier for those already on the keto diet and are metabolically flexible.
Like regular fasting, dry fasting benefits include weight loss, decreased inflammation, slower aging, better insulin sensitivity, and clearer skin.
The tips we’ve just shared will help you with dry fasting as a beginner but speak with a healthcare provider for further guidance and advice.