Fasting involves abstaining from food for a specific duration, but an increasing number of people are choosing to practice “dry fasting,” which eliminates all food and liquids, including water.
While some purported health benefits include reduced inflammation, improved skin condition, and weight reduction, scientific research supporting these claims remains somewhat limited.
Although individuals fast for various purposes—including religious practices, weight management, and cognitive enhancement—medical experts have raised concerns about dry fasting and its potential hazards when practiced for extended periods.
Registered dietitian Julia Zumpano discussed dry fasting with Cleveland Clinic, explaining that if people choose this method to improve their health, it may not deliver the expected results.
“There’s just not a lot of data on it,” she noted. “There are some studies with people who are following Ramadan fasts, but when it comes to the general public, there’s not a lot of good data. Dry fasting can lead to dehydration, kidney issues and cause other symptoms that aren’t worth the risk. With other forms of fasting, you can get the benefits of fasting without dehydrating yourselves.”
Zumpano outlined additional concerning risks, stating: “Dry fasting can also cause, urinary, kidney and lungs issues, as well as nutritional deficiencies and eating disorders.”
Additional symptoms include fatigue, irritability, headaches, difficulty concentrating, reduced urination, and constipation.
A detailed analysis has demonstrated what occurs in your body during a 36-hour dry fast, revealing some alarming developments.
Physiological Changes During a 36-Hour Fast
Four Hours
According to a 55-second video published on YouTube by Wellness Wise on May 6, your body ceases food digestion after four hours of fasting.
Popular practitioner Dr. Kiltz describes this as the “catabolic phase.” On his website, he explains this period as being “characterized by the breakdown of larger molecules of stored energy into smaller energy molecules which are mobilized to fuel your cells.”
Eight Hours
This marks the point when blood sugar levels begin declining, prompting your body to utilize stored glycogen for energy rather than depending on incoming fuel sources.
12 Hours
After twelve hours, your body’s glucose reserves become depleted, causing your liver to begin converting fat into fatty acids called ketones.
This conversion process is termed “metabolic switching” and, according to the BBC, explains why fasting can result in weight loss.
16 Hours
A cellular mechanism called autophagy begins after 16 hours without food consumption.
According to Cleveland Clinic, this process enables cells to break down damaged components and repurpose usable materials into new, functional cellular parts.
24 Hours
A complete day without food represents a significant duration for most people, but this 24-hour milestone marks when substantial cellular repair occurs in the human body.
The YouTube video, which has accumulated over eight million views, indicates that your body enters full fat-burning mode, reducing inflammation and enhancing insulin sensitivity.
30 Hours
Growth hormone levels increase significantly after 30 hours of fasting, which reportedly helps maintain muscle mass while promoting fat loss.
36 Hours
Reaching the 36-hour mark means achieving maximum autophagy, where your body allegedly regenerates tissues and accelerates metabolism.
Despite these described processes, medical professionals emphasize that the risks associated with dry fasting, particularly dehydration and organ dysfunction, may outweigh any potential benefits. Traditional fasting methods that allow water consumption can provide similar advantages without the dangerous side effects of complete fluid restriction.