Studies have shown that intermittent fasting can improve your health and increase longevity.
This type of fasting takes water out of the equation. If the first question that pops into your head was “wouldn’t I get dehydrated?”, you’re in good company. Most people brush off dry fasting as something dangerous that should never be attempted, and there’s a lot of misinformation out there that fuels this fear.
Dry fasting can be extremely beneficial to cell regeneration and repair. And dry fasting can be done safely as long as you take all the steps necessary to do it right.
In this article you’ll learn everything about how dry fasting works, why it works, and if you should try it:
WHAT IS DRY FASTING?
Dry fasting is a type of fast that doesn’t allow any water intake. The lack of water may help accelerate some of the protective effects you get on a regular water fast, like reduced inflammation and metabolic health. Dry fasting is lesser known than water fasting and often considered dangerous, however, millions of people around the world actually do a dry fast for a month each year. During Ramadan (a month-long intermittent dry fast), Muslims fast without consuming water or food during daylight hours (12 hours on average).
The benefits of fasting are backed by research. Studies find that caloric restriction or fasting can enhance longevity, increase neurogenesis (neuron production), lower oxidative markers, balance insulin levels, and improve brain plasticity. Dry fasting is associated with significantly reduced inflammation, lower blood pressure, and balanced glucose[*][*].
Just like regular fasting, dry fasting can be intermittent or prolonged.
INTERMITTENT DRY FASTING
You can do an intermittent dry fast by eating and drinking only for a small window of time each day and fasting the remaining hours. The recommended distribution can be:
- 16/8 intermittent fasting:You’d eat in a window of 8 hours and fast for 16 hours. This is the most common type of intermittent fasting.
The dry fast done during Ramadan mimics a traditional intermittent fasting. People consume one meal in the morning, abstain from food and water for 10-18 hours a day, and then eat dinner late at night. This refuels their body before the next day’s fast.
Intermittent dry fasting is the best approach because it lets you to reap the health benefits of the fast without endangering your health.
You may wonder if a dry fast has any serious advantages over a water fast that will make it worth your while.
Dry Fasting vs. Water Fasting
Water-based intermittent fasting has impressive health benefits, like fighting cancer cells, neuroprotection, improved insulin sensitivity, promoting a longer and healthier lifespan, reduction of fat tissue, cellular repair through autophagy, and sustained ketosis. When you fast, you allow your body to regenerate, heal, and get rid of harmful agents more easily. An intermittent dry fast can further intensify this cleansing process without dehydrating you.
Get this: Limited fluid intake pushes your body to burn more fat since fat can be used to produce metabolic water (water that your body makes internally). For every 100 grams of fat, your body can make 107-110 grams of water, compared to 60g from carbs and just 42g of water from protein.[*][*][*][*] In other words, fat is the most efficient source of internal water. Since you won’t be hydrating your body with external liquids, metabolic water is of extreme importance and your body will strive to make it from fat at a higher rate than it would on a water fast.
Given that fat is necessary for a successful dry fast, it’s ideal if you do it while following the ketogenic diet. High-fat meals in between the fast will help you breeze through it with minimal discomfort.
Dry Fasting In The Ketogenic Diet
Dry fasting on the keto diet is easier because you’ll experience less hunger, less thirst, less discomfort, and your body can produce more metabolic water from fat. One study compared the effects of eating a meal high in fat, protein, or carbs before a traditional 12-hour dry fast.
People who ate fat before fasting had the lowest amount of discomfort compared to people relying on carbs or protein, and they also experienced less hunger and thirst compared to the high-protein group.
People relying on the high-protein diet had the most discomfort and side effects (11 vs. 3 just after fatty meals).[*]
Eating fat before the fast also provided these perks:
- Post-fasting systolic and diastolic blood pressures decreased significantly.
- Post-fasting glucose also decreased.
Fasting while on the ketogenic can also improve brain function and energy, because the blood-brain barrier becomes more permeable to ketones during any type of fast[*].
Here’s how a combining the keto diet with a dry fast can protect your brain:
- The fast makes your brain more receptive to ketones through a permeable blood-brain barrier.
- Having fewer liquids in your system means more fat burning to create metabolic water.
- More fat burning means more ketones in your bloodstream.
- Having more ketones in your system means more energy available for your brain.
A third advantage of dry fasting on the ketogenic diet is that fat can help suppress your perceived need for water.
This even happens to people who aren’t fasting. The more someone eats fat, the less they tend to drink water, according to research. On the other hand, foods like fiber, caffeine, and alcohol trigger a higher water consumption[*][*].
The Top 8 Health Benefits of Dry Fasting
Dry fasting can protect your brain, metabolism, and prevent disease through impressive anti-inflammatory effects. Here are the top benefits of fasting without water
#1: ENHANCED COGNITIVE FUNCTION AND PROTECTION
An intermittent dry fast can have these effects on your brain:
- Increased neuron protection against dysfunction and degeneration
- Increased creation of new neurons
- Increased brain plasticity
- Decreased neuronal excitotoxicity
One study found that a Ramadan dry fast increased the levels of a neurotrophin called BDNF (brain-derived neurotrophic factor)[*]. Neurotrophins are proteins that promote the survival and growth of neurons.
The roles of BDNF are maintaining memory and learning capacity, regulating neurogenesis and neuronal survival in the adult brain, and metabolic regulation. In fact, it’s one of the proteins responsible for the positive adaptations of the brain in situations when there’s little food available[*][*][*].
Even a short-term fast can improve brain function by killing harmful or unnecessary cells through autophagy[*].
Another way a dry fast protects the brain is through ketone production. Ketone bodies reduce two things in your brain: glutamate (an excitotoxin that can cause neuronal death if unregulated) and oxidative stress[*].
#2: HIGH ANTI-INFLAMMATORY ACTIVITY
When you’re dry fasting, your inflammation levels plummet.
- TNF-α: This molecule is able to induce fever, inflammation, and cell death. It can increase the chance of Alzheimer’s disease, cancer, psoriasis, and inflammatory bowel diseases when it’s not properly regulated.
- CRP: High levels of CRP are associated with an increased risk of diabetes, hypertension, and cardiovascular disease
- IL-1b: Important mediator of inflammation and is linked to heart failure.
- IL-6:This proinflammatory molecule can worsen autoimmune diseases and infections. It’s associated with a higher risk of diabetes, juvenile rheumatoid arthritis, and further malignant growths in people with breast cancer.
- CXC Chemokines: Molecules that cause inflammation when unregulated.
Intermittent dry fasting also reduces inflammation by decreasing the levels of leukocytes (immune cells), because leukocyte-derived inflammatory molecules contribute to inflammatory diseases[*].
By reducing inflammation, a dry fast can help prevent many degenerative diseases.
#3: BALANCED LIPIDS
Dry fasting can positively affect levels of triglycerides, good cholesterol, bad cholesterol, and total cholesterol.
Several studies show that after dry fasting[*]:
- HDL (good) cholesterol levels increased in women.
- Total cholesterol and triglycerides decreased in men.
- LDL (bad) cholesterol decreased in both sexes.
Interestingly, the quality of the fats you eat before and after your fast can affect your lipid levels.
For instance, people dry fasting in Morocco had a significant reduction in total cholesterol and triglycerides even one month after the fast had ended. Meanwhile, people in Kuwait doing the same fast had no significant changes in cholesterol or triglycerides[*][*][*].
This difference may be explained by the different fats consumed in each country. The positive effect on Moroccans was associated with a higher consumption of monounsaturated and polyunsaturated fatty acids, while Kuwait is more focused on saturated fat[*]. If you eat different fats before doing a dry fast, you’re more likely to experience lipid control.
#4: GLYCEMIC CONTROL
A dry fast can also regulate blood sugar, another important metabolic marker. This is no surprise, considering that the protective effects of fasting are in part thanks to a 50% reduction in glucose and insulin-like growth factor 1 (IGF-I).[*]
#5: DIABETES PREVENTION
Thanks to its glycemic benefits, dry fasting may prevent the onset of diabetes.
In some communities who dry fast for 24 hours, studies find a lower incidence of diabetes. From the study groups, 20% of non-fasters had diabetes while only 10% of fasters had developed diabetes[*].
Another study found that patients with type 2 diabetes who did an intermittent dry fast for 15–21 days had a significant reduction of hemoglobin A1c (HbA1c) levels, which is an indicator of the average blood sugar concentration[*].
#6: LOWER BLOOD PRESSURE
Many studies find that people have a lower systolic blood pressure at the end of dry fasts,[*] and these effects may be greater on a keto diet. One study found that blood pressure had decreased after people ate either carbs, protein, or fat before the fast, but only those who ate fat had a remarkable reduction[*].
#7: PREVENTION OF CORONARY HEART DISEASE
Dry fasting may lower the risk of coronary heart disease. Studies done on people who dry fast for 24 hours find they have a lower prevalence of coronary heart disease compared to non-fasters, even after adjusting for other risk factors[*].
#8: BONE HEALTH
A molecule called parathyroid hormone (PTH), which is vital for bone formation and integrity, is increased during dry fasting. This spike in PTH leads to bone resorption, bone formation, and increased calcium levels during and after a dry fast[*].
Dry Fasting Stages
When you fast, your body will go through two stages of fuel burning:
Stage #1: Burning Glycogen (If You’re Not Fat-Adapted)
When there’s no food or water, your body will try to burn stored glycogen if you’re not fat-adapted. This burning mode can last 2-3 days, so this would be the only fuel in an intermittent dry fast. Burning glycogen instead of fat will make your body produce less metabolic water and might cause more discomfort.
Stage #2: Burning Fat
You can take a shortcut and start burning fat from day one by adopting a ketogenic diet. Using fat from the start will help you stay hydrated, lower thirst, prevent discomfort, and enter ketosis much faster. Now that you know how dry fasting works, here’s how to do it in a safe way:
Dry Fasting The Right Way
Dry fasting can improve many metabolic markers and protect against disease if you do it under the right conditions. Here’s how to make it work:
WHO SHOULD DRY FAST?
- Someone who has plenty of experience with water fasts and has had no side effects from them.
- Someone who is fat-adapted.
- People who aren’t prone to migraines or headaches.
- Someone who isn’t coffee or tea-dependent.
- People without any eye-related diseases.
WHO SHOULD TAKE CAUTION DURING DRY FAST?
- People who have never tried water fasts before, or those who have only done juice fasts.
- People who are prone to headaches or migraines, because a dry fast can trigger them[*].
- People dependent on stimulants like coffee and tea, because the withdrawal during the fast can cause headaches and moodiness[*].
- People with dry eye syndrome, glaucoma, or cataracts. Dry fasting has been shown to exacerbate the symptoms in these conditions[*].
HOW LONG CAN I DRY FAST?
An intermittent dry fast of 16 hours per day is ideal. Intermittent dry fasting has been the most researched, while there’s no evidence to guarantee the safety of dry fasts that last more than a day. drinking plenty of water to hydrate your body.
MISTAKE #1: EXERCISING TOO HARD
Excessive sweating will increase water loss, messing with your body’s efforts to maintain water balance. This can dehydrate you and make you light-headed. If possible, save your intense gym sessions for before or after the fast. You can also opt for light exercise instead.
MISTAKE #2: IGNORING YOUR BODY
Ignoring your body’s signals is the worst mistake you can make on any fast. Pay attention to how you’re feeling throughout the dry fast and don’t hesitate to break the fast if you feel something’s not right. You might need to shorten the length of your fast or adjust some other lifestyle factors like exercise or caffeine.
Fact-checked by Dr. Anthony Gustin, DC, MS