Ettelbruck

Long COVID, characterized by ongoing symptoms such as fatigue, cognitive difficulties, and respiratory problems following COVID-19 infection, affects many patients and significantly lowers quality of life. This study investigates the feasibility of a 7-day ambulatory fasting intervention using the Buchinger-Wilhelmi method, a structured medically supervised fasting approach, to assess its potential benefits on clinical, biological, and psychological aspects of long COVID over 4 weeks. Participants will undergo a bowel cleanse followed by a week of fasting with a limited calorie intake of up to 350 kcal per day, mainly from vegetable broths and juices, along with calorie-free water or tea. The fasting period is preceded by three days of reduced food intake and is followed by three days of gradually increasing food intake. The intervention is supported by detailed instructions, face-to-face consultations, and a smartphone app for adherence monitoring. Throughout the 4-week study, participants will have blood, stool, urine, saliva samples collected for various analyses including immune markers, microbiome composition, and metabolomics. They will complete questionnaires on fatigue, quality of life, anxiety, depression, mood, and functionality. Safety and adherence will be monitored regularly through clinical assessments, telephone follow-ups, and digital app questionnaires to evaluate the fasting methods impact and feasibility for long COVID treatment.