Effect of Intermittent Versus Continuous Energy Restriction on Compensatory Mechanisms Activated During Weight Reduction

Study Overview
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Brief Summary
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Obesity has become a global epidemic with huge public health implications. Although clinical significant weight loss can be achieved by a combination of diet and behavioral modification, strong metabolic adaptations, with increased appetite and suppressed energy expenditure, are activated, which compromise weight loss maintenance and increase the risk of relapse. The aim of this project is to compare the effects of intermittent versus continuous energy restriction on the compensatory responses previously described using two low calory diets, with a similar macronutrient distribution. More specifically, this study will analyze, in the short-term, if an intermittent energy restricted diet is associated with less appetite and low reduction in energy expenditure when compared with a continuous energy restricted diet. This project can bring large practical benefits concerning the design of weight loss programs to minimize weight relapse.

Official Title
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Effect of Intermittent Versus Continuous Energy Restriction on Compensatory Mechanisms Activated During Weight Reduction

Conditions
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Obesity

Intervention / Treatment
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* Behavioral: Intermittent energy restricted diet
* Behavioral: Continuous energy restricted diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: adult (18-50 years old) obese healthy volunteers (30<BMI<40 kg/m2) weight stable on the last three months (<2kg), not currently dieting to lose weight and with an inactive lifestyle Exclusion Criteria: history of endocrine/cardiovascular/pulmonary/kidney disease anaemia milk intolerance depression or other psychological disorders eating disorders drug or alcohol abuse within the last two years current medication known to affect appetite or induce weight loss a planned surgery during the study period participating in another research study

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intermittent energy restricted diet<br>The intermittent energy restricted group will undergo 3 nonconsecutive days of partial fasting per week. During the 3 days of partial fasting, participants will be asked to consume a very-low calorie diet (VLCD) providing 550kcal/day for women and 650kcal/day for men. The VLCD products provide 110kcal/pack and include a variety of shakes, smoothies and soups. For the feeding days a diet matching energy needs will be prescribed, using meal replacements (such as smoothies, soups and cereal bars) and conventional food. Drinking at least 2.5 liters of non-caloric liquids will be recommended. | Behavioral: Intermittent energy restricted diet<br> <br> |
| Experimental: Continuous energy restricted diet<br>The continuous energy restricted group will be prescribed a low calorie diet (LCD) with 33% energy restriction, using meal replacements (such as smoothies, soups and cereal bars) and conventional food. The diets' macronutrient composition of the two groups will be matched (50% carbohydrates, 20% protein and 30% fat). | Behavioral: Continuous energy restricted diet<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Appetite related hormones | Appetite-related hormones (active Ghrelin, PYY, GLP-1, CCK) will be measured in fasting and every 30 minutes up to 2,5 hours. | 12 weeks after the intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Resting metabolic rate (RMR) | RMR measured by indirect calorimetry | 12 weeks after the intervention | 
| Exercise efficiency | Exercise efficiency measured by graded exercise on a bike | 12 weeks after the intervention | 
| Body composition | RMR measured by indirect calorimetry | 12 weeks after the intervention | 
| Body composition | RMR measured by indirect calorimetry | At 6 months from baseline | 
| Body composition | RMR measured by indirect calorimetry | At 1 year from baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Weight loss, Intermittent energy restriction, Metabolic compensation, Diet therapy