Extended Evening Fasting: Metabolic Health and Energy Balance

Study Overview
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Brief Summary
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This study will compare metabolic and feeding behaviour responses to 4 days of extended evening fasting vs. a control trial

Detailed Description
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Humans have evolved as a diurnal species, internally governed by the circadian system, which dictates our hormone regulation. 'Chrononutrition' is a sub-discipline which combines food timing with circadian physiology. The most popular method of time-restricted feeding in the UK is to skip breakfast. However, data from several meta-analysis have shown that skipping breakfast is associated with weight gain and insulin resistance, likely due to eating later into the evening/night and therefore, out of sync with our circadian rhythm. Recent research has shown that skipping dinner (evening fasting) has improved markers of cardio-metabolic health in clinical populations, although these are typically from longer-term studies. Despite these promising findings, it is not yet known whether these findings are population specific. Therefore, the investigators are interested in examining the metabolic response pre and post intervention to see whether these promising findings can translate into a healthy population. Furthermore, the investigators will be monitoring subjective appetite, energy intake and expenditure to assess whether there is any short-term adaptation to a specific feeding window.

Official Title
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The Effect of 4 Days of Extended Evening Fasting on Metabolic Health, Energy Balance and Appetite

Conditions
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Obesity

Intervention / Treatment
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* Behavioral: Extended Evening Fasting
* Behavioral: Control


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Non-smokers. Have maintained a stable weight for 6 months (self-reported). No history of gastric, digestive, cardiovascular or renal disease (self reported). Female specific: must be using a monophasic, low dose combined OCP (containing less than 50μg oestradiol and a synthetic progestin) OR females with regular menstrual cycles (self-reported). Exclusion Criteria: Severe food allergies, dislike or intolerance of study foods or drinks. Currently undergoing a lifestyle intervention (structured diet or exercise) Diagnosis of a condition or currently undergoing treatment therapy known to affect glucose or lipid metabolism (e.g., type-2 diabetes, taking statins), or contraindications to exercise. Use of medication or supplements that may affect hormone concentrations. Excessive alcohol consumption (>14 units/week). Intensive training schedule (>10 hours/week). Female specific: currently pregnant or breastfeeding, the use of any hormonal contraception, and the self-reporting of short (<24 d), long (>35 d), or irregular menstrual cycles.

Ages Eligible for Study
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Minimum Age: 18 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: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: The study design is a randomised, controlled, crossover design in which participants undertake two conditions in a randomised order with at least four weeks in between trials.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Extended Evening Fasting<br>Participants will eat between 8am-4pm | Behavioral: Extended Evening Fasting<br>* Participants will undertake 4 days of extended evening fasting (feeding between 8am-4pm). The participants will visit the laboratory on day 1, following a 16 h fast, where baseline measures will be taken and the response to a standardised meal will take place. The participant will also have an opportunity to feed ad-libitum before they leave the laboratory. The participant will continue to adhere to the feeding window on day 2 and day 3, although this will be in free-living conditions. On day 4, the participant will arrive back to the lab for post-intervention assessment, identical in format to day 1 with a metabolic assessment and energy intake assessment via a ad-libitum meal.<br>|
| Active Comparator: Control<br>Participants will eat between 8am-8pm | Behavioral: Control<br>* Participants will undertake 4 days of a standard western feeding pattern (feeding between 8am-8pm). The participants will visit the laboratory on day 1, following a 12 h fast, where baseline measures will be taken and the response to a standardised meal will take place. The participant will also have an opportunity to feed ad-libitum before they leave the laboratory. The participant will continue to adhere to the feeding window on day 2 and day 3, although this will be in free-living conditions. On day 4, the participant will arrive back to the lab for post-intervention assessment, identical in format to day 1 with a metabolic assessment and energy intake assessment via a ad-libitum meal.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Glycaemic control (Baseline) | A metabolic assessment lasting 3.5 hours will take place following a standardised, laboratory-based meal. The investigators will be taking periodic capillary and venous blood samples to measure post-prandial glucose and insulin, which together comprise 'glycaemic control'. | 3.5 hours following the standardised breakfast meal on day 1. | 
| Glycaemic control (Post intervention) | A metabolic assessment lasting 3.5 hours will take place following a standardised, laboratory-based meal. The investigators will be taking periodic capillary and venous blood samples to measure post-prandial glucose and insulin, which together comprise 'glycaemic control'. | 3.5 hours following the standardised breakfast meal on day 4. | 
| Energy Intake (Kilocalories) | Energy intake will be measured both during lab and outside of the laboratory when the participants are free-living. During lab, energy intake will be measured through ad-libitum feeding buffet where 20 minutes will be permitted to eat as much or as little as they desire, until 'comfortably full and satisfied', followed by post-feeding measurement of the remaining food. Outside of laboratory feeding will also be monitored through food diary's and weighing any investigator issued meals. | Day 1 to day 4. | 
| Energy expenditure | Energy expenditure will be measured via a chest-worn device (Actiheart) which combines heart rate and accelerometry to gauge calories expended. | Day 1 to day 4. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cortisol awakening response | The cortisol awakening response will be measured on the final morning of each trial. | Five samples will be collected by the participant within the first hour of waking on day 5. | 
| Visual Analogue Scale for Subjective Ratings of Appetite | Subjective appetite will be measured on mobile devices via a software which replicates a 100mm visual analogue scale. The scale is divided into subscales of different appetite perceptions including: hunger, fullness, desire to eat and prospective food consumption. (i.e. from 0 - 100), with a rating of 100 fully supporting the perception and a rating of 0 fully opposing the perception. | Every 2 hours between 8am-10pm from day 1 to day 4. | 
| Acylated Ghrelin (appetite hormone) | Acylated Ghrelin will be measured from the venous samples taken during the post-prandial period following the standardised meal. | 3.5 hours following the standardised breakfast meal on day 1 and day 4. | 
| PYY (appetite hormone) | PYY will be measured from the venous samples taken during the post-prandial period following the standardised meal. | 3.5 hours following the standardised breakfast meal on day 1 and day 4. | 
| Carbohydrate oxidation | Investigators will be collecting expired air into Douglas bags, and measuring the VO2 and VCO2 concentration to calculate carbohydrate oxidation. | During laboratory visits on day 1 and day 4 [baseline, 60min, 120min, 180min] | 
| Fat oxidation | Investigators will be collecting expired air into Douglas bags, and measuring the VO2 and VCO2 concentration to calculate fat oxidation. | During laboratory visits on day 1 and day 4 [baseline, 60min, 120min, 180min] | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Chrononutrition, Energy balance, Intermittent fasting, Appetite hormones