Bariatric Surgery Candidate, Obesity, Morbid, PreDiabetes
Conditions
Keywords
Prediabetes, Bariatric Surgery, Low-carb diet
Brief summary
To investigate the metabolic effects of a low carbohydrate versus energy-matched standard diet in morbidly obese individuals with prediabetes awaiting bariatric surgery.
Detailed description
The metabolic benefits of calorie restriction in obese people with or without impaired glycaemia are well-established. The impact of diet composition, however, remains poorly understood. Hepatic lipid content strongly correlates with hepatic insulin resistance, which is a key feature of the pre-diabetic state. The investigators hypothesize that a low carbohydrate diet compared to an energy-matched standard diet in morbidly obese patients with prediabetes scheduled for bariatric surgery results in greater reduction in liver fat.
Interventions
OTHERLow carbohydrate diet
A energy deficient (30% deficit) low carbohydrate diet (10% of carbohydrates)
OTHEREnergy-matched standard diet
Energy-matched (30% deficit) standard diet (50% of carbohydrates)
Sponsors
Insel Gruppe AG, University Hospital Bern
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
SINGLE (Subject)
Intervention model description
Single-centre, randomized parallel study
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Female and male subjects aged 18 years or older * BMI \>35 kg/m2 awaiting bariatric surgery * Pre-diabetes according to American Diabetes Association criteria (HbA1c 5.7%-6.4%) * Capacity to give informed consent and adhere to study procedures
Exclusion criteria
* Excess alcohol consumption (\> 3 units/day for men, \> 2 units/day for women) * Moderate to severe kidney disease * Nephrolithiasis * Pregnancy/breastfeeding * Current participation in another clinical trial * Claustrophobia * MRI-contraindications (pacemaker/defibrillator, neurostimulator, drug pump, cochlear implant, heart valve/vascular clips, shunt valve)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change from baseline in intrahepatic triglyceride content | 2 weeks | The intrahepatic triglyceride content will be evaluated by magnetic resonance spectroscopy |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change from baseline in body weight | 2 weeks | The body weight will be measured using a pre-defined person scale |
| Change from baseline in liver size | 2 weeks | The liver size will be evaluated by magnetic resonance imaging |
| Change from baseline in insulin secretion | 2 weeks | The insulin secretion will be evaluated during an oral glucose tolerance test using the oral minimal model |
| Change from baseline in whole body fat mass | 2 weeks | Fat mass will be evaluated by bioimpedance |
| Change from baseline in insulin sensitivity | 2 weeks | The insulin sensitivity will be evaluated during an oral glucose tolerance test using the oral minimal model |
| Change from baseline in visceral adipose tissue | 2 weeks | The adipose tissue content will be evaluated by magnetic resonance imaging |
Other
| Measure | Time frame | Description |
|---|---|---|
| Change in immunometabolism of T-cells | 2 weeks | Immunometabolism will be assessed by quantifying rates of oxygen consumption and glycolysis using metabolic flux analysis |
| Change from baseline in plasma metabolome | 2 weeks | Fasting serum sampling |
| Length of hospital stay | Day of surgery until 2 weeks post-surgery | Based on medical records |
| Occurrence of surgical complication | Day of surgery until 2 weeks post-surgery | Occurrence of the following: anastomotic leak, infection, bleeding, deep venous thrombosis (based on medical records) |
| Change from baseline in plasma transcriptome | 2 weeks | Fasting serum sampling |
| Change from baseline in Fibroblast Growth Factor 21 | 2 weeks | Plasma level |
| Change from baseline in adipose tissue inflammation | 2 weeks | Adipose tissue histology |
| Change from baseline in gut microbiota composition | 2 weeks | Distribution of the predominant bacterial phylotypes will be assessed after 16S rRNA amplicon sequencing and subsequent taxonomic classification |
| Change from baseline levels of secondary bile acids | 2 weeks | Faecal sampling |
| Change in frequency of immune cells (T-, B-, NK-cells, monocytes, neutrophils) | 2 weeks | Frequency of immune cells will be analysed using flowcytometry |
Countries
Switzerland
Outcome results
None listed