A Low Glycemic Index Diet as Prevention of the Catch-up Fat Phenomenon

Study Overview
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Brief Summary
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The catch-up fat phenomenon is an evolutionary conserved physiological response to a starvationrefeeding cycle. It is characterized by long-term suppression of thermogenesis, reduced body protein regain and an increase in fat mass above basal level during refeeding. Clinically, it characterises weight cycling in overweight patients which is associated with increasing fat mass (visceral fat) and increased morbidity (e.g. insulin resistance, inflammation). In this project, the physiological, cellular and molecular mechanisms of this phenomenon will be investigated in humans, mice and C. elegans. It is hypothesized that refeeding a low GI (=glycemic index)- diet after weight loss prevents the catchup fat phenomenon and its sequelae. This translational research will provide comprehensive insights into the catch-up fat phenomenon as well as provide a suitable strategy of its prevention.

Detailed Description
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In a human intervention study, changes in physiological, metabolic, and neuroendocrine functions in response to weight cycling will be investigated under controlled conditions in normal weight subjects. The mechanisms of the catch-up fat phenomenon are analysed starting from stable energy balance followed by overfeeding, weight loss and weight regain following weight loss (refeeding). Changes in body composition (including ectopic fat), metabolism (resting energy expenditure, substrate oxidation rates, insulin resistance) and plasma hormone concentrations will be assessed. Fat tissue probes will be used to characterise key enzymes and signalling pathways, redox status and whole genome expression. Modulation of the hormonal response to weight cycling is brought about by varying macronutrient content and glycemic index of the diets. We hypothesize that, insulin and leptin resistance are explained by increased insulin secretion during the refeeding period. Both, adaptive thermogenesis as well as insulin and leptin resistance can be ameliorated by attenuation of the increase in insulin and leptin secretion during refeeding a low GI diet after weight loss.

Official Title
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Ätiologie, Pathophysiologie Und Prävention Einer überschießenden Körperfettzunahme Nach Gewichtsreduktion - Vermeidung Des JoJo-Effektes in Der Behandlung Von Übergewicht

Conditions
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Dietary Intervention

Intervention / Treatment
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* Other: dietary intervention by varying GI diets


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: normal weight (BMI 20-24 kg/m2), normal fat mass Exclusion Criteria: smoking, chronic diseases, drug intake, nutrient allergies, lactose intolerance, pacemaker, metalliferous implants

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: low GI, low GI<br>low GI diet (semi starvation phase) followed by low GI diet in the refeeding phase | Other: dietary intervention by varying GI diets<br>* The human study intends to characterise the partitioning of weight gain during refeeding and to affect the catch-up fat phenomenon by the glycemic index (GI) of the diet.<br>|
| Experimental: low GI, high GI<br>low GI diet (semi starvation phase) followed by high GI diet in the refeeding phase | Other: dietary intervention by varying GI diets<br>* The human study intends to characterise the partitioning of weight gain during refeeding and to affect the catch-up fat phenomenon by the glycemic index (GI) of the diet.<br>|
| Experimental: high GI, low GI<br>high GI diet (semi starvation phase) followed by low GI diet in the refeeding phase | Other: dietary intervention by varying GI diets<br>* The human study intends to characterise the partitioning of weight gain during refeeding and to affect the catch-up fat phenomenon by the glycemic index (GI) of the diet.<br>|
| Experimental: high GI, high GI<br>high GI diet (semi starvation phase) followed by high GI diet in the refeeding phase | Other: dietary intervention by varying GI diets<br>* The human study intends to characterise the partitioning of weight gain during refeeding and to affect the catch-up fat phenomenon by the glycemic index (GI) of the diet.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in body composition and energy metabolism after 3 weeks of underfeeding and 2 following weeks of refeeding | Body composition measurement including BODPOD, QMR, BIA Energy Metabolism measurement using indirect calorimetry | Body composition measurement after 4 and 6 study weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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partitioning of weight gain, refeeding, catch-up fat phenomenon, glycemic index