Tests an antibiotic after weight loss in adults with recurrent obesity
Tests an oral antibiotic or placebo in adults with obesity to prevent weight regain.
Plain-language title generated from the registry record
Registry title: The Role of Microbiome in Recurrent Obesity Before and After Antibiotic/Placebo Treatment
Key facts
- Where
- Rehovot, IsraelSee the site
Could this be for you?
Answer for yourself. This is not a decision: only the study team can say whether you can take part.
- Are you between 18 and 65 years old?
Source: NCT06681246, who can take part
Where in Israel
- Weizmann Institute of ScienceRehovot, IsraelTaking people
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Trial details
- Who runs it
- Weizmann Institute of Science
- Trial code
- NCT06681246
- Record updated
- 11 August 2026
- Original description
This past century witnessed a significant increase in the prevalence of obesity. Successful weight loss maintenance is defined as losing at least 10% of the initial body weight and maintaining it for at least one year. However, keeping a low body weight is rarely maintained, as 80% of people who lost 10% of their body weight will return to their initial weight within a year. Although there is no agreement as to what contributes to the recurrent weight regain phenomenon (also known as 'weight cycling' or 'yo-yo diet'), it is strongly associated with the risk of developing metabolic risk factors and their complications, including heart disease and all-cause mortality. Altering the gut microbiota is one method to treat disease states associated with gut bacteria. Antibiotics consumption is known to influence host glycemic response through changes induced in microbiome composition and function. Therefore, it may be a possible pathway to jumpstart changes in the gut microbiota.Read full original descriptionShow less
The Role of Microbiome in Recurrent Obesity Before and After Antibiotic/Placebo Treatment
This past century witnessed a significant increase in the prevalence of obesity. Successful weight loss maintenance is defined as losing at least 10% of the initial body weight and maintaining it for at least one year. However, keeping a low body weight is rarely maintained, as 80% of people who lost 10% of their body weight will return to their initial weight within a year. Although there is no agreement as to what contributes to the recurrent weight regain phenomenon (also known as 'weight cycling' or 'yo-yo diet'), it is strongly associated with the risk of developing metabolic risk factors and their complications, including heart disease and all-cause mortality. Altering the gut microbiota is one method to treat disease states associated with gut bacteria. Antibiotics consumption is known to influence host glycemic response through changes induced in microbiome composition and function. Therefore, it may be a possible pathway to jumpstart changes in the gut microbiota.
This study will determine whether microbiome modulation might be a possible future target against recurrent obesity in humans and whether orally administered antibiotic treatment post-weight loss might be an effective intervention to prevent weight regain.
Inclusion: 28 < BMI< 40; Age - 18-65; Capable of working with a smartphone application.
Exclusion: Consumption of antibiotics/probiotics/oral antifungals 2 months prior to the first day of the experiment; Pregnancy, fertility treatments, breastfeeding women six months prior to enrollment and during the study; Bariatric surgery; Weight loss attempts 6 months prior to the first day of the experiment - using weight loss medication; Drastic changes in nutritional habits six months prior to the first day of the study - to the discretion of the study team; Chronic disease, to the discretion of the study team (e.g. AIDS, Cushing syndrome, CKD, acromegaly etc.); Cancer and recent anticancer treatment; Psychiatric disorders, to the discretion of the study team; Coagulation disorders; IBD (inflammatory bowel diseases); Eating disorders (Anorexia nervosa. Bulimia nervosa. Binge eating disorder, Night eating syndrome); Allergy to penicillin; History of CDI; Liver disease; History of serious unresolved diarrhea in response to antibiotic treatment to the discretion of the study doctor; Alcohol or substance abuse; Life threatening reaction after consumption of cephalosporins.