Low Energy Ketogenic Diet in Obese Subjects - the Impact on Whole Organism

Study Overview
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Brief Summary
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The study evaluates the timeline of changes of body composition, physical and psychological performance, and biochemical markers of metabolism and inflammation responses to low energy ketogenic diet for loosing weight in obese individuals. The participants will be monitored and guided by the interdisciplinary obesity team for 12 weeks.

Detailed Description
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Ketogenic diets have been shown to be an effective tool to fight obesity with reported good adherence due to their ability to suppress the drive to eat. They are also gaining popularity in public, despite some concerns regarding the quality and timeline of changes of body composition and the effects on health parameters of whole organism. For effective weight loss, energy deficit is required. Very low energy (600 - 800 kcal) ketogenic diets have been extensively studied. The proposed study combines low energy (800 - 1500 kcal) and ketogenic diet intervention. The aim of the study is a comprehensive determination of quality of body mass loss, metabolic states changes, physical and psychological performance changes, and inflammatory and hormones profile changes during and post a 12-week low energy ketogenic diet intervention.

Official Title
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The Safety and Effects on Whole Organism of Low Energy Ketogenic Diet for Weight Loss in Obese Subjects

Conditions
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Obesity

Intervention / Treatment
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* Behavioral: Low energy ketogenic diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: BMI > 30 kg/m2 asymptomatic for any disease except obesity Exclusion Criteria: presence of cardiovascular, endocrine, acute or chronic inflammatory diseases; taking medications for lipid metabolism, or psychiatric disorders; adherence to a prescribed diet; unstable weight in the past 3 months; BMI < 30 kg/m2; unwilling or unable to eat the foods prescribed in the study; vigorous physical activity; pregnancy or lactation.

Ages Eligible for Study
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Minimum Age: 25 Years
Maximum Age: 55 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
Intervention Model: Single Group Assignment
Interventional Model Description: Longitudinal intervention study with repeated measurements. Participants will be subjected to a 12-week low energy ketogenic diet (LEKD) and requested not to change their physical activity levels throughout the study. The participants will underwent a series of tests and consultations at baseline (prior to the start of the intervention), and after 1, 2, 4, 8 , and 12 weeks of LEKD intervention. At the end of each time points, body weight and composition will be measured in the fasting state, food and exercise diaries checked by a dietitian and a kinesiologist and discussed with the participants, psychological and cognitive tests will be performed by a psychologist. At the same time-points, different serum analyses will be performed.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: participants<br>The participants will be subjected to low energy ketogenic diet. | Behavioral: Low energy ketogenic diet<br>* Low energy ketogenic diet lasting 12 weeks with a previous preparation period including detailed instructions during classes and individual counselling by a dietitian. Participants were provided with a list of suitable foods with very low carbohydrate content. Furthermore, the subjects shared cooking recipes and links to helpful webpages. They were free to follow a KD according to their personal preferences but limit their carbohydrate intake to 5-10 % of total energy from carbohydrates, but derive at least 70 % of total energy from fat.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in body composition | Body mass, fat free body mass and fat mass will be measured (all in kilograms) with bioelectrical impedance analysis (BIA) Tanita BC 418MA. | Change from baseline over 12 weeks with intermediate time points at 1, 2, 4 and 8 weeks. | 
| Change in beta-hydroxybutirate | Overnight fasted serum beta-hydroxybutirate will be determined (in mmol/l). | Change from baseline over 12 weeks with intermediate time points at 1, 2, 4 and 8 weeks. | 
| Change in resting energy rate | Resting energy rate will be determined with indirect calorimetry. | Change from baseline to 12 weeks. | 
| Change in physical fitness | Physical fitness will be determined using 2 km walking test according to the UKK Walk Test Programme. | Change from baseline to 12 weeks. | 
| Change in cognitive functions | Will be assessed by validated psychological test (Wechsler Adult Intelligence Scale - Forth Edition (WAIS-IV). | Change from baseline to 12 weeks. | 
| Change in psychological factors | Will be assessed by validated psychological test (Dutch Eating Behavior Questionnaire (DEBQ). | Change from baseline to 12 weeks. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in body weight following intervention | Maintenance of body mass at the end of intervention will be evaluated over the 12 months following intervention (in kilogrames). | Change from 12 weeks to 12 months. | 
| Adherence to ketogenic diet | Adherence to ketogenic diet will be assessed by 3-day food record. | At 12 months. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ketogenic diet, body composition, metabolism, body dissatisfaction, cognition