Ketogenic diet before bariatric surgery

The Impact of a Preoperative Very Low Calorie Ketogenic Diet (VLCKD) on Body Composition in Patients Undergoing Bariatric Surgery: a Randomised Controlled Trial

NA · Maxima Medical Center · NCT06850493

This study is testing if a very low-calorie ketogenic diet can help people lose weight and reduce liver size before bariatric surgery, compared to a standard low-calorie diet.

Quick facts

PhaseNA
Study typeInterventional
Enrollment46 (estimated)
Ages18 Years to 65 Years
SexAll
SponsorMaxima Medical Center (other)
Locations1 site (Veldhoven, North Brabant)
Trial IDNCT06850493 on ClinicalTrials.gov

What this trial studies

This study investigates the effects of a very low-calorie ketogenic diet (VLCKD) on patients preparing for bariatric surgery. It aims to compare the VLCKD with standard very low-calorie diets (VLCD) to assess weight loss and liver volume reduction while preserving lean body mass. The trial will involve a randomized controlled design to provide robust data on the efficacy of VLCKDs in this context. The study is motivated by the need for improved preoperative dietary regimens that can enhance surgical outcomes and reduce complications.

Who should consider this trial

Good fit: Ideal candidates are individuals eligible for bariatric surgery with a BMI of 35 kg/m2 or higher and obesity-related comorbidities.

Not a fit: Patients who weigh over 150 kg or have certain medical conditions such as type 1 diabetes or recent heart issues may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could lead to better preoperative weight loss and improved surgical outcomes for bariatric surgery candidates.

How similar studies have performed: While few small studies have explored VLCKDs prior to bariatric surgery, this trial aims to provide more comprehensive data, making it a novel approach.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Eligible for bariatric surgery (≥35 kg/m2 with obesity-related comorbidities, or a BMI of

  * 40 kg/m2 with or without comorbidities)
* Roux-en-Y Gastric bypass (RYGB)

Exclusion Criteria:

* Weighing over 150kg because this amount is a limitation by the DXA device
* Diabetes mellitus type 1
* Allergic to milk proteins
* A recent history of a heart attack (\< 12 months), heart failure or cardiac arrhythmias
* Kidney and/or liver failure (creatinine levels \>1.3 mg/dl or liver enzyme levels (AST, ALT, GGT)) less than three times over the upper normal threshold
* Current infectious, sepsis or malignant disease
* Rare condition like galactosemia, phenylketonuria or porphyria
* Persistent diarrhoea
* Hypokalaemia, chronic therapies with diuretics as furosemide and hydrochlorothiazide
* Pregnancy or plans to get pregnant in the coming months
* Patients who did not meet criteria to be eligible for bariatric surgery (BMI \<35, psychological or unstable psychiatric disorders, inadequate dietary regimen or inadequate exercise pattern which can't be resolved in the upcoming 6 months)

Where this trial is running

Veldhoven, North Brabant

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Bariatric Surgery Candidate, Ketogenic Dieting

Last reviewed 2026-05-15 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.