Effects of Early and Delayed Time-restricted Eating in Adults With Overweight and Obesity

Study Overview
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Brief Summary
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Time-restricted eating (TRE) is a dietary approach that aims to increase fasting time and decrease the eating window. Promising TRE effects on weight loss and some cardiometabolic risk factors have been reported. However, there is a lack of randomized clinical trials that directly investigate the effect of TRE at different times of the day (early vs. delayed) in individuals with overweight and obesity. The present study investigates the effects of 8 weeks of TRE performed at different moments of the day on body composition and cardiometabolic parameters in adults with overweight and obesity.

Official Title
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Effects of Early and Delayed Time-Restricted Eating on Body Weight and Metabolic Parameters in Adults With Overweight and Obesity

Conditions
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Intermittent Fasting, Obesity, Overweight and Obesity, Time Restricted Feeding

Intervention / Treatment
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* Behavioral: Dietary Approach


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male and female; Body mass index (BMI) between 25 and 34.9 kg/m²; Age between 20 and 40 years; Not engaged in any structured exercise program; Weight stable for  3 months prior to the beginning of the study; Able to give written informed consent. Exclusion Criteria: Current smoker; Cardiometabolic diseases (dyslipidemia, diabetes, hypertension, etc); Current treatment with medication or supplements which significantly affect the main studied variables; Night-shift workers; Night eating syndrome; Irregular sleep patterns; For women: pregnancy, planned pregnancy (within the study period), lactating or menopause; Habitual fasting window >16 hours; Concomitant participation in other studies.

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Early Time-Restricted Eating<br>8-hour eating window between 08:00 and 16:00 | Behavioral: Dietary Approach<br>* Dietary approaches with energy restriction performed at different times of the day.<br>|
| Experimental: Delayed Time-Restricted Eating<br>8-hour eating window between 12:00 and 20:00 | Behavioral: Dietary Approach<br>* Dietary approaches with energy restriction performed at different times of the day.<br>|
| Experimental: Control<br>12-hour eating window between 08:00 and 20:00 | Behavioral: Dietary Approach<br>* Dietary approaches with energy restriction performed at different times of the day.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Insulin resistance (indices) | Including but not limited to Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). | Change from baseline. Measured at baseline and after 8 weeks. | 
| Fasting insulin levels (µIU/mL) | Measured by enzyme-Linked Immunosorbent Assay | Change from baseline. Measured at baseline and after 8 weeks. | 
| Fasting glucose levels (mg/dL) | Measured by colorimetric method | Change from baseline. Measured at baseline and after 8 weeks. | 
| Insulin Sensitivity (indices) | Including but not limited to the Matsuda index | Change from baseline. Measured at baseline and after 8 weeks. | 
| Glucose tolerance | Measured by oral glucose tolerance test (OGTT; 0,30,60,90, and 120 min) | Change from baseline. Measured at baseline and after 8 weeks. | 
| Fasting lipid profile levels (mg/dL) | Measured by colorimetric method | Change from baseline. Measured at baseline and after 8 weeks. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| β cell function (indices) | Including but not limited to HOMA-BETA | Change from baseline. Measured at baseline and after 8 weeks. | 
| Fat Mass (kg) | Measured by Dual-energy X-ray Absorptiometry under fasting condition. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Fat Percentage (%) | Measured by Dual-energy X-ray Absorptiometry under fasting condition. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Fat Free Mass (kg) | Measured by Dual-energy X-ray Absorptiometry under fasting condition. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Body Weight (kg) | Measured by Dual-energy X-ray Absorptiometry under fasting condition. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Body Weight (kg) | Measured on a digital scale. | Change from baseline. Measured at baseline and after 4, and 8 weeks. | 
| Bone Mineral Content (kg) | Measured by Dual-energy X-ray Absorptiometry under fasting condition. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Body Mass Index (kg/m^2) | Calculated from weight in kilograms divided by height in meters squared. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Fasting ketones (β-hydroxybutyrate) levels (mmol/L) |  | Change from baseline. Measured at baseline and after 8 weeks. | 
| Resting metabolic rate (Kcal/day) | Measured by indirect calorimetry under resting and fasting conditions. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Substrate Oxidation (respiratory exchange ratio) | Measured by indirect calorimetry under resting and fasting conditions. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Peak oxygen consumption (mL/min and mL/kg/min) | Measured by an open-circuit spirometry system | Change from baseline. Measured at baseline and after 8 weeks. | 
| Quality of sleep | Measured by Pittsburgh Sleep Quality Index Questionnaire. Higher scores indicate worse sleep quality. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Risk of binge eating | Measured by binge eating scale. Higher scores indicate greater risk of binge eating. | Change from baseline. Measured at baseline and after 8 weeks. | 
| Subjective appetite parameters (hunger, fullness, prospective food consumption, and desire to eat). | Measured by visual analog scale.The scale range is 0-100 mm and each end represent the extremes. | Change from baseline. Measured at baseline and after 8 weeks. |