Clinical trial Recruiting at 1 site Interventional Ages 18 and up

Combining a very low calorie ketogenic diet with naltrexone/bupropion for weight regain after bariatric surgery

Official title: Naltrexone/Bupropion With or Without Very Low Calorie Ketogenic Diet for Weight Regain After Bariatric Surgery

Run by Universitaire Ziekenhuizen KU Leuven · NCT06881485 · Data updated 2026-11-12

This study is testing if a very low calorie ketogenic diet combined with a medication can help people who have regained weight after bariatric surgery lose weight again.

More Obesity (Disorder) trials

Quick facts

Study typeInterventional
Ages18 Years and up
SexAll
Enrollment62 (estimated)
SponsorUniversitaire Ziekenhuizen KU Leuven
Academic / other
Locations2 sites (Leuven, Vlaams-Brabant and 1 other locations)
StatusRecruiting
StartedJanuary 20, 2025
Main results expectedJanuary 1, 2027
Study endsJanuary 1, 2027
Registry record updatedMarch 21, 2025
Trial IDNCT06881485 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates are adults aged 18 and older who have undergone bariatric surgery and have experienced a weight regain of 10% or more of their lowest weight.

Probably not a fit

Patients with Type 2 diabetes or those who have not regained weight after bariatric surgery may not benefit from this study.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This clinical trial evaluates the effectiveness of a very low calorie ketogenic diet (VLCKD) combined with naltrexone/bupropion (N/B) compared to standard care with N/B alone for individuals who have experienced weight regain after bariatric surgery. The primary goal is to measure the percentage of weight loss at 26 weeks, while secondary endpoints include weight loss percentages at various intervals and patient-reported outcomes related to hunger and cravings. Participants will be monitored for adherence to the diet and medication, as well as the tolerability of the interventions over a year-long period.

Why it matters

Potential benefit: If successful, this approach could provide a new effective strategy for managing weight regain in patients post-bariatric surgery.

How similar studies have gone: While there is limited data on this specific combination, similar approaches using dietary interventions and pharmacotherapy have shown promise in managing obesity.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Participants eligible for inclusion in this Trial must meet all of the following criteria:

  1. Voluntary written informed consent of the participant or their legally authorized representative has been obtained prior to any screening procedures
  2. Use of highly effective methods of birth control; defined as those that, alone or in combination, result in low failure rate (i.e., less than 1% per year) when used consistently and correctly; such as implants, injectables, combined oral contraceptives, some IUDs, true sexual abstinence (i.e. refraining from heterosexual intercourse during the entire period of risk associated with the Trial treatment(s)) or commitment to a vasectomised partner.
  3. Miminum 18 years of age at the time of Informed Consent signature
  4. Underwent bariatric surgery (RYGB or SG) with weight regain ≥10% of nadir weight
  5. People without Type 2 diabetes (T2D) • No history, no drugs, HbA1c \< 6,5% and FPG \<126 mg/dl) All participants that are considered for Trial participation, per the above criteria will be documented on the Screening Log, including Screen Failures.

Exclusion Criteria:

* Participants eligible for this Trial must not meet any of the following criteria:

  1. Participant has a history of type 2 diabetes mellitus (also drugs, HbA1c \> 6,5% and FPG \>126 mg/dl)
  2. IFemale who is pregnant, breast-feeding or intends to become pregnant or is of child-bearing potential and not using an adequate, highly effective contraceptive
  3. Participation in an interventional Trial with an investigational medicinal product (IMP) or device
  4. Not willing to sign informed consent
  5. Younger than 18 years of age at the time of Informed Consent signature
  6. Other types of bariatric surgery other than RYGB or SG (including LAGB, BPD)
  7. Underwent bariatric surgery (RYGB or SG) with weight regain \<10% of nadir weight
  8. Contraindication for VLCKD, including CKD stage 4-5, liver cirrhosis, type 1 diabetes mellitus, active gout
  9. Contraindication for NB including the use of opioids, history of CNS tumor or seizures, severe psychiatric disorder or \> 2 psychotropic medications, uncontrolled hypertension
  10. Use of other drugs for weight management (e.g. GLP1Ra) in the last 3 months prior to trial intervention
  11. Any disorder, which in the Investigator's opinion might jeopardise the participant's safety or compliance with the protocol Participants who meet one or more of the above exclusion criteria must not proceed to be enrolled/randomized in the Trial and will be identified on the Screening Log as Screen Failure.

Where it's running

  • UZ Leuven
    Leuven, Vlaams-Brabant, Belgium
    Recruiting
  • AZ Sint-Jan Brugge
    Bruges, West-Vlaanderen, Belgium
    Not yet recruiting

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.