Safety, health improvement and well-being during a 4 to 21-day fasting period in an observational study including 1422 subjects

Abstract

Only few studies document longer periods of fasting in large cohorts including non-obese participants. The aim of this study was to document prospectively the safety and any changes in basic health and well-being indicators during Buchinger periodic fasting within a specialised clinic. In a one-year observational study 1422 subjects participated in a fasting program consisting of fasting periods of between 4 and 21 days. Subjects were grouped in fasting period lengths of 5, 10, 15 and 20±2 days. The participants fasted according to the Buchinger guidelines with a daily caloric intake of 200–250 kcal accompanied by a moderate-intensity lifestyle program. Clinical parameters as well as adverse effects and well-being were documented daily. Blood examinations before and at the end of the fasting period complemented the pre-post analysis using mixed-effects linear models. Significant reductions in weight, abdominal circumference and blood pressure were observed in the whole group (each p<0.001). A beneficial modulating effect of fasting on blood lipids, glucoregulation and further general health-related blood parameters was shown. In all groups, fasting led to a decrease in blood glucose levels to low norm range and to an increase in ketone bodies levels (each p<0.001), documenting the metabolic switch. An increase in physical and emotional well-being (each p<0.001) and an absence of hunger feeling in 93.2% of the subjects supported the feasibility of prolonged fasting. Among the 404 subjects with pre-existing health-complaints, 341 (84.4%) reported an improvement. Adverse effects were reported in less than 1% of the participants. The results from 1422 subjects showed for the first time that Buchinger periodic fasting lasting from 4 to 21 days is safe and well tolerated. It led to enhancement of emotional and physical well-being and improvements in relevant cardiovascular and general risk factors, as well as subjective health complaints.

Human Postprandial Nutrient Metabolism and Low-Grade Inflammation: A Narrative Review

“…A four week regimen of 800 kcal per day in obese women decreased LBP, CRP, gut permeability as well as insulin resistance [153]. In the observational study of Toledo et al [154], healthy subjects and subjects with pre-existing conditions followed a fasting regimen with a low caloric intake of around 225 kcal for 4 to 21 days. From the group with pre-existing conditions which included inflammatory diseases, 84% reported clinically relevant improvement in their symptoms after fasting [154].…”

“…In the observational study of Toledo et al [154], healthy subjects and subjects with pre-existing conditions followed a fasting regimen with a low caloric intake of around 225 kcal for 4 to 21 days. From the group with pre-existing conditions which included inflammatory diseases, 84% reported clinically relevant improvement in their symptoms after fasting [154]. According to this, repeated cycles of three day fasting improved symptoms and alleviated demyelinisation in mice from an experimental model mimicking multiple sclerosis, which is, like RA, an immune-mediated inflammatory disease [155].…”

“…Furthermore, mediation of T cell immunity was supressed after a three day fasting period in female Mongolian gerbils [165]. Fasting in humans decreased leukocyte counts by 0.4-1 × 10 3 /µL depending on the length of fasting, from 5-20 days, respectively [154]. Whether these reductions in leukocyte count are sufficient to decrease the inflammatory effects of auto-immune diseases remains to be elucidated.…”

Changes in human gut microbiota composition are linked to the energy metabolic switch during 10 d of Buchinger fasting

“…documented to safely enhance well-being and to have therapeutic benefits (3,4) . Most scientific investigations in the last decade were, however, focused on intermittent fasting, a recurrence of 16 to 48 h energy restriction alternating with food intake (3) .…”

“…In other words, there is a metabolic switch in energy utilisation from glucose to fatty acids and ketones. This increase in the rate of lipolysis and ketogenesis is reflected by a decrease in blood glucose, insulin, insulin-like growth factor-1, concomitant to an increase in glucagon, growth hormone, NEFA, ketone bodies and insulin-like growth factor binding protein-1 levels (4,(7)(8)(9) .…”