Dry fasting, the practice of going without food and water, has enthusiastic advocates on TikTok, X, YouTube, and other social media platforms. Devotees claim a wide range of health effects, but medical professionals advise caution to ensure that the practice does more good than harm, especially for individuals with diabetes.
Purported benefits and risks vary, depending on who is following the regimen and how long they abstain from food and water. Advocates on social media assert that dry fasting makes “intuition skyrocket” and puts autophagy on “overdrive.” Although such statements may rev up followers, there is little evidence to support these and many other dry-fasting claims. In fact, several physicians warned about unintended consequences.
“I had one patient who followed this fasting method often, and over time she developed kidney stones that led to a severe infection,” said Deena Adimoolam, MD, an endocrinologist in private practice in New York City and New Jersey. “Lack of both water and food can fuel hunger and increase the likelihood of overeating or binge eating once the fast is completed, which does not lead to weight loss. Untreated dehydration can lead to loss of consciousness.”
“For individuals with type 2 diabetes, dehydration can exacerbate hyperglycemia and increase the risk of complications such as diabetic ketoacidosis (DKA),” said Abeer Bader, lead clinical nutrition specialist at the Massachusetts General Hospital Weight Center in Boston. “Research also consistently shows that adequate hydration is crucial for maintaining physical and cognitive performance.”
, Ms. Bader noted. “Prolonged dry fasting can result in nutrient deficiencies. For individuals with diabetes, maintaining adequate nutrition is crucial to manage blood sugar levels and overall health. The lack of both food and water can exacerbate deficiencies.”
Joanne Bruno, MD, an endocrinologist at NYU Langone Health, added, “Certain medications used for the management of type 2 diabetes, such as SGLT2 inhibitors, can cause dehydration. It is critical that patients stay well hydrated while on these medications to avoid serious side effects such as euglycemic DKA.”
What Exactly Is Dry Fasting?
Defining dry fasting, like any kind of fasting, has remained a challenge, according to authors of the first international consensus on fasting terminology, published on July 25 in Cell Metabolism. The clinical terminology “has remained heterogeneous and often confusing, with similar terms being used to define different fasting regimens ... reflecting the manifold contexts in which fasting is practiced.”
Indeed, dry fasting was among the most discussed terms by the consensus panel and went through several rounds before the panelists came to agreement. A few experts were critical of the practice, whereas those familiar with religious fasting traditions, such as during Ramadan, were clear about the importance of including this term in the consensus process.
“The dissent was resolved by the clarification that this form of fasting has historical and geographical extensions and that the present consensus process did not aim at evaluating therapeutic effectiveness or safety for any term defined,” the authors wrote.
The panel concluded that dry fasting is not the same as total or complete fasting because the latter can include water (such as water-only fasting). Their final definition of dry fasting is ‘’a fasting regimen during which a voluntary abstinence from all foods and beverages, including water, is practiced for a certain period of time.’’
Different types of fasting regimens, such as intermittent fasting, may include dry fasting, in which case it is referred to as “intermittent dry fasting.” This is defined in the consensus as intermittent fasting regimens that involve abstaining from food and fluid intake during the fasting interval, which typically lasts 9-20 hours.
Most dry fasts, including religious ones, are maintained for a specific interval and are followed by a refeeding period. These fasts are not starvation, defined as no food or water intake for days.