Is Water-Only Fasting Safe?

Abstract

Background Water-only fasting (WF) is a practice used to improve and maintain health. Objective The aim of the study was to show whether WF performed for 8 days may be a threat to the health and/or life of people undergoing this practice. Methods Twelve middle-aged men participated in the study. During the 8-day WF, the subjects ate no food except for drinking mineral water. Before and after WF, all subjects had a series of tests performed, beginning with the level of perceived stress and somatic measurements. The concentrations of creatinine, sodium (Na+), potassium (K+), total calcium (Ca), magnesium (Mg++), urea (U), uric acid (UA) and total protein were determined in this urine and in the serum. For these substances, the values ​​of clearance, renal filtration and fractional excretion were calculated. The osmotic clearance and free water clearance as well as the amount of daily urinary excretion of creatinine, Na+, K+, Ca, Mg++, U and UA were also calculated. Moreover, the concentration of glucose in the serum and the concentration of β-hydroxybutyrate in the plasma were determined. In urine, specific gravity, pH and osmolality were also measured. Results After 8 days of WF, the study showed a significant reduction in the level of perceived stress, weight loss, changes in body composition, dehydration, increased ketogenesis, hyperuricemia, decreased serum glucose concentration, and hyponatremia. These changes were accompanied by Na+, K+ and protein sparing, decreased serum Ca and Mg++ concentrations, and reduced daily volume of more acidic urine with elevated specific gravity. Conclusions After 8 days of WF, all subjects were found to remain safe and feel the sense of well-being. However, the appearance of the above-mentioned adverse metabolic effects, despite partially effective renal compensations, suggests that the further continuation of fasting intervention by the subjects would be detrimental to their body.

Prolonged Fasting as a Cause of Deep Vein Thrombosis: A Case Report

“… 1 Various forms of fasting exist but medical supervision is usually recommended, especially when food restriction is more important or for a prolonged period of time. 2 3 4 …”

“…Nevertheless, potential health benefits are still reported after shorter course of water-only fasting done under appropriate medical supervision. 4 8 9 However, safety of such food restriction is still not well established and relies on limited data. 4 5 …”

“… 4 8 9 However, safety of such food restriction is still not well established and relies on limited data. 4 5 …”

“…1 Various forms of fasting exist but medical supervision is usually recommended, especially when food restriction is more important or for a prolonged period of time. [2][3][4] Water-only fasting is defined by restriction of every type of food (zero-calorie diet) except water. In the 1960s and 1970s, fasting duration of 60 days and more was considered for important weight loss, but this practice has been abandoned due to important complications and deaths.…”

“…6,7 Nevertheless, potential health benefits are still reported after shorter course of water-only fasting done under appropriate medical supervision. 4,8,9 However, safety of such food restriction is still not well established and relies on limited data. 4,5 We describe the case of a man who developed a right lower limb proximal deep vein thrombosis (DVT) in the context of unsupervised water-only fasting.…”