Understanding Dry Fasting: The Extreme Approach

Dry fasting is defined as total food and water deprivation, meaning you do not eat or drink for a period of time. Sometimes, intermittent dry fasting occurs as part of religious ceremonies or traditions (e.g., Ramadan, Yom Kippur). However, it remains controversial, as the potential for dry fasting, especially longer than 12 hours, can lead to significant dehydration, electrolyte abnormalities, and other serious complications.

The Growing Popularity: Why Dry Fasting is Gaining Attention

Dry fasting has gained much attention over recent years due to suspected improvements in metabolism, immune function, insulin sensitivity, inflammation, heart health, brain health, and cellular repair; however, research is scarce. Several studies have observed intermittent dry fasting and its effects on day dry fasting (i.e. fasting from dawn to dusk or 12-hour periods) and seen improvements as mentioned above. One study found that daytime dry fasting in a small group of individuals fasting for Baha’is led to improved fat metabolism and no adverse effects on hydration. Still, these individuals could drink and/or eat after sundown. Very few studies have identified the effects of dry fasting on the general population, not to mention those with chronic diseases.

The Dangers of Dehydration: The Primary Health Risk

The Human Body and Water: A Vital Necessity

The human body is approximately 60% water and relies on water to function and survive. Water is important because it helps carry nutrients and oxygen to cells, protects our organs and tissues, regulates body temperature, promotes kidney function, and removes waste products from our bodies. We need water!

The Symptoms of Dehydration: Recognizing the Signs

Dehydration occurs as a result of losing more fluid than what you are able to take in. If you are dry fasting, you may not have enough water to keep your fluid levels up. Signs of dehydration are extreme thirst, dry mouth and tongue, dark-colored urine, less frequent urination, fatigue, headaches, sunken eyes/cheeks, poor skin turgor, dizziness, and confusion. If you start to notice these signs, it is crucial to seek medical attention if you are not able to replenish fluids orally. The majority of the time, someone who has been sick with a gastrointestinal bug, experiences excessive sweating due to physical activity, and individuals undergoing certain pharmaceutical treatments with side effects are most likely to experience dehydration.

Severe Consequences: The Dangers of Prolonged Dehydration

Prolonged dehydration is a significant issue of concern. You might end up with a kidney injury, brain damage, seizures, refeeding syndrome, shock, stroke, heart attack, coma, and death. Therefore, being on top of drinking fluids and eating is key to maintaining electrolyte homeostasis.

Other Health Risks Associated with Dry Fasting

Electrolyte Imbalances: A Serious Concern

Before I talk about the detrimental effects of electrolyte imbalance, it is important to understand the basics of why electrolytes are important for health.

Sodium – aids in maintaining blood pressure and volume and regulates osmotic pressure and water distribution in the body. It also helps with muscle and nerve impulses.

Potassium – supports muscle contraction and nervous system communication. It is also crucial for cellular metabolism and the making of glycogen and protein (important factors for energy in the body).

Magnesium – supports over 300 enzyme reactions in the body. It is important for creating protein, DNA, and energy in the body. It also aids in muscle contraction and nerve impulses.

Phosphorus – supports energy production, getting oxygen from the blood into tissues, glucose utilization, protein creation, and neurologic and muscle function. It also helps maintain body pH.

Calcium – aids in maintaining bone structure, blood clotting, platelet adhesion, and endocrine and exocrine functions. It is also a key player in supporting smooth muscle contractions of the heart and lungs.

Bicarbonate – acts as a buffer in the blood, maintaining blood pH and carbon dioxide levels, which impacts breathing.

Chloride – maintains the body’s acid-base balance, regulating blood pH.

So now that you understand why electrolytes are important, you can imagine what would happen if you were deficient. As previously mentioned, serious complications like kidney injuries, brain damage, coma, and death can occur. However, uncomfortable symptoms like muscle cramping and confusion occur.

Kidney Injury and Other Health Issues

Kidney injury is common among dehydrated individuals because the kidneys are primarily responsible for filtering and maintaining electrolyte levels and fluid balance within the body. Kidney injury can be marked by reduced urine output, increased electrolyte levels, decreased kidney filtration, and excess fluid retention. Chronic kidney disease is the gradual loss of kidney function over time due to multiple factors. With dehydration, acute kidney injury is most common and may lead to irreversible kidney damage, which in turn leads to chronic kidney disease.

Refeeding syndrome occurs as a result of metabolic changes that occur due to acute malnutrition. As a practicing clinician, I have seen this a handful of times, typically in individuals who have prolonged starvation and little fluid intake for several days. Once food is re-introduced, the body has difficulty adapting to the nutrient intake, and therefore, the metabolic processes that have changed cannot tolerate the significant intake. This can lead to alterations in electrolytes, leading to other complications, as mentioned. I wouldn’t be shocked to see dry fasting lead to this in individuals already under metabolic stress for different reasons like illness.  

The Impact on Mental Health

Besides all of the detrimental effects of dehydration that have been previously listed, mental health can take a serious hit as well. If you’ve ever been dehydrated or hungry for a period of time, you might have experienced some confusion, difficulty concentrating, difficulty making decisions, lethargy, and irritability, which can make it very challenging for you to function in your normal routines and activities. With the inability to think clearly you won’t be able to make clear decisions for yourself, which could significantly impact your health.

Seeking Professional Guidance: The Importance of Medical Consultation

When to Consult a Doctor: Assessing Your Health Status

You should seek medical attention if you are unable to maintain adequate hydration, especially in circumstances where you are losing excess fluid (i.e. diarrhea, vomiting, and excessive sweating). Additionally, if you are considering following a diet like dry fasting, it is crucial to discuss with your healthcare provider to assess if this is safe for you to do; even in instances of religious traditions, some individuals are exempt from dry fasting due to medical comorbidities.

If you are pregnant, breastfeeding, have existing cardiac or renal impairment, or are already malnourished, you should avoid dry fasting as this could be detrimental.

Safer Alternatives: Exploring Other Healthy Habits

If you're looking to lose weight, there are many effective approaches supported by research. Strategies may include mindful eating patterns, balanced meal planning, or adjusting macronutrient intake to suit your needs. Consulting with a registered dietitian can provide personalized guidance to help you achieve and maintain a healthy weight in a sustainable way.

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