While body weight reduction can be achieved through various interventions in people living with obesity, most patients regain a substantial proportion of the lost weight within the following months. There is a lack of effective interventions to prevent this regain, making weight regain one of the most pressing challenges in obesity management. The goal of this clinical trial is to determine whether adhering to time-restricted eating (TRE; a form of intermittent fasting) during and after a dietary weight loss intervention, promotes weight maintenance to a greater extent than consuming all daily meals within 12 hours or more. Additionally, the study will address other questions, such as whether TRE improves body composition, insulin sensitivity, and cardiometabolic risk factors; whether the TRE intervention produces effects on different components of energy balance or related behaviors; and whether prior exposure to the TRE intervention influences eating window duration and weight change over the subsequent 24 months. The study will compare participants who concentrate all their food intake within 8 hours or less with those who consume all their daily meals within 12 hours or more. All participants will follow a calorie-restricted diet designed to induce an 8-10% weight loss over 12-16 weeks and will be followed for several months after the weight loss intervention.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
212
Calorie restriction intervention consisting on a meal plan designed to induce an 8-10% weight loss over a 12-16 week period.
Receiving instructions to maintain their regular eating window (12h/d or more) both during the 12-16 weeks of calorie restriction and the 12 months following its completion.
Receiving instructions to confine all daily meals to a period of 8 hours or less (at least 6 days a week) both during the 12-16 weeks of calorie restriction and the 12 months following its completion.
Department of Physiology, Faculty of Medicine, University of Granada.
Granada, Granada, Spain
RECRUITINGChange in weight (Kg) during the 6 months following the end of the calorie restriction intervention
Time frame: 6 after the end of the dietary intervention - End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss).
Weight (Kg)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention
Waist circumference (cm)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Hip Circumference (cm)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Fat mass (kg) by DXA
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Fat free mass (kg) by DXA
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Fat mass (kg) by Bioimpendaciometry
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Fat free mass (kg) by Bioimpendaciometry
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Body Mass Index (kg/m2)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Resting Energy Expenditure (kcal/day) measured by indirect calorimetry
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Posprandial Energy Expenditure (kcal/day) measured by indirect calorimetry
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Fasting nutrient utilization rates (g/min) measured by indirect calorimetry and protein excretion
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Postprandial nutrient utilization rates (g/min) measured by indirect calorimetry and protein excretion
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Energy Intake (kcal) in an Ad-Libitum Meal Test
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Energy efficiency (W/KJ) while cycling, assessed by indirect calorimetry
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Maximal fat oxidation (g/min) by indirect calorimetry
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Physical activity (counts/day) measured by accelerometry
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 after the end of dietary intervention.
Sedentary time (min/day) measured by accelerometry
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention
Habitual food consumption collected by a food frecuency questionnaire
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Serum Total Cholesterol (mg/dl)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum LDL cholesterol (mg/dl)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum HDL cholesterol (mg/dl)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum triglycerides (mg/dl)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum glucose (mg/dl)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum insulin (U/ml)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum hemoglobin A1c (mmol/mol)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum thyrotropin (µU/mL)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum Alanine Transaminase (U/L)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention
Serum Aspartate Transaminase (U/L)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum gamma-glutamyl transferase (U/L)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Serum C-reactive protein (mg/dL)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Craving Control measured using the Control of Eating Weekly Questionnaire (CoEQ)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Positive Mood measured using the Control of Eating Weekly Questionnaire (CoEQ)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Craving for Sweet Foods measured using the Control of Eating Weekly Questionnaire (CoEQ)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Craving for Savory Foods measured using the Control of Eating Weekly Questionnaire (CoEQ)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Fasting appetite-related sensations measured using "Visual Analogue Scales (VAS)"
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Meal-induced changes in appetite-related sensations measured using "Visual Analogue Scales (VAS)" in response to a meal
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Fasting Liking and Wanting measured using Leeds Food Preference Questionnaire
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Liking and Wanting in response to a meal measured using Leeds Food Preference Questionnaire
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Meal-induced changes in serum glucose concentration (mg/dL) in response to a standardized meal
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Meal-induced changes in serum insulin concentration (U/ml) in response to a standardized meal
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Cognitive restriction of food intake measured using the "Three-Factor Eating Questionnaire"
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Food disinhibition measured using the "Three-Factor Eating Questionnaire"
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Subjective hunger measured using the "Three-Factor Eating Questionnaire"
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Binge eating behavior measured using the "Binge Eating Questionnaire"
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Sleep time (min) measured by accelerometry
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Handgrip strength (kg) measured using a dynamometer
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Functional mobility measured by "Timed Up and Go (TUG)" test
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Walking speed (m/s) measured by a gait speed test
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Independence in activities of daily living (ADL) measured by "Barthel Index"
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention
Food cravings measured using the "Food Craving Inventory" questionnaire
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention
Carbohydrate intake (g/day) collected through three 24-hour recalls
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Fat intake (g/day) collected through three 24-hour recalls
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Protein intake (g/day) collected through three 24-hour recalls
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Fiber intake (g/day) collected through three 24-hour recalls
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Changes in appetite-related sensations measured using "Visual Analogue Scales (VAS)" in response to a submaximal stress test
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 6 months after the end of dietary intervention.
Resting heart rate variability
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Resting Systolic blood pressure (mmHg)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
Resting Diastolic blood pressure (mmHg)
Time frame: Baseline; End of dietary intervention (Week 12/16, depending on achievement of 8-10% weight loss); 1, 3, 6, 12, 18, 24 and 36 months after the end of dietary intervention.
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