Metabolic Effects of a Low Carbohydrate Versus a Standard Diet in Morbidly Obese With Prediabetes

Study Overview
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Brief Summary
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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
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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.

Official Title
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Metabolic Effects of a Low Carbohydrate Versus Energy-matched Standard Diet in Morbidly Obese Individuals With Prediabetes

Conditions
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PreDiabetes, Obesity, Morbid, Bariatric Surgery Candidate

Intervention / Treatment
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* Other: Low carbohydrate diet
* Other: Energy-matched standard diet


Participation Criteria
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Eligibility Criteria
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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)

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Single-centre, randomized parallel study
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Study intervention<br>Participants will follow an energy deficient (30% deficit) low carbohydrate diet (10% of carbohydrates) for minimum two weeks. | Other: Low carbohydrate diet<br>* A energy deficient (30% deficit) low carbohydrate diet (10% of carbohydrates)<br>|
| Active Comparator: Control intervention<br>Participants will follow an energy deficient (30% deficit) standard diet (50% of carbohydrates) for minimum two weeks. | Other: Energy-matched standard diet<br>* Energy-matched (30% deficit) standard diet (50% of carbohydrates)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in intrahepatic triglyceride content | The intrahepatic triglyceride content will be evaluated by magnetic resonance spectroscopy | 2 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in body weight | The body weight will be measured using a pre-defined person scale | 2 weeks | 
| Change from baseline in liver size | The liver size will be evaluated by magnetic resonance imaging | 2 weeks | 
| Change from baseline in visceral adipose tissue | The adipose tissue content will be evaluated by magnetic resonance imaging | 2 weeks | 
| Change from baseline in whole body fat mass | Fat mass will be evaluated by bioimpedance | 2 weeks | 
| Change from baseline in insulin secretion | The insulin secretion will be evaluated during an oral glucose tolerance test using the oral minimal model | 2 weeks | 
| Change from baseline in insulin sensitivity | The insulin sensitivity will be evaluated during an oral glucose tolerance test using the oral minimal model | 2 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Prediabetes, Bariatric Surgery, Low-carb diet