Effects of Two-weeks of Time Restricted Feeding on Basal and Postprandial Metabolism in Healthy Men

Study Overview
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Brief Summary
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In the modern era, food access is widely available and it is not uncommon for the time between breakfast and a late night snack to exceed 14 hours. The investigators are interested in studying whether limiting this window to 8 hours will have any beneficial effects of human health as has been demonstrated in animal models. Eight men were asked to restrict their energy intake window to between 8 am and 4 pm for two weeks whilst maintaining their habitual diet (quantity and composition). Improvements in skeletal muscle and whole-body insulin sensitivity were observed but these were potentially confounded by an average weight loss of 1 kg. Therefore an additional control group was recruited to follow a daily caloric deficit of  400 kilocalories without changing the timing of intake.

Detailed Description
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All participants were monitored for a one week baseline period to establish their habitual physical activity and dietary patterns. This was done using food diaries, interstitial glucose monitors and a combined heart rate + accelerometer device. Participants consumed a standardised evening meal  12h before visiting the laboratory to assess their metabolic response to a liquid test meal (1g/kg bodyweight dextrose and 0.4g/kg bodyweight protein) using the arterio-venous forearm balance model. Dual-energy X-ray absorptiometry scans, indirect calorimetry measurements and fasted and postprandial vastus lateralis biopsies were also obtained. From the next day, participants either restricted their daily energy intake window to between 8 am and 4 pm or were prescribed a caloric deficit diet ( 400 kilocalories/day) for two weeks. Physical activity, interstitial glucose concentrations and dietary patterns were monitored throughout. After this, participants visited the laboratory again to assess changes in metabolism and body composition.

Official Title
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Effects of Two-weeks of Time Restricted Feeding on Basal and Postprandial Metabolism in Healthy Men

Conditions
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Metabolic Health

Intervention / Treatment
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* Behavioral: Time restricted feeding
* Behavioral: Caloric restriction


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy male between 18 and 35 years old Body mass index between 18 and 27.5 kg.m^-2 Regular breakfast consumer, 5 or more days per week Moderate physical activity level (PAL between 1.6 and 2) Exclusion Criteria: Smoking Any metabolic (e.g. diabetes), endocrine (e.g. hyperthyroidism) or cardiovascular (heart or blood) abnormalities including hypertension. Clinically significant abnormalities on screening including ECG abnormalities Routine medication that may alter cardiovascular function and blood flow (e.g. blood pressure-lowering drugs or drugs that cause hypertension) High alcohol consumption (Routinely >4 units per day) Eating attitudes test (EAT-26) score > 20 On an energy-restricted diet Significant body mass fluctuation in previous 3 months (>5%)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: All participants monitored for a one week baseline period before being allocated to either a caloric deficit group or a time-restricted feeding group for two weeks.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Time restricted feeding (TRF)<br>Participants restricted their daily energy intake window to between 8 am and 4 pm for two weeks. They were encouraged to not alter the quantity and composition of their diet or alter physical activity patterns. | Behavioral: Time restricted feeding<br>* Restrict energy intake window to between 8am and 4pm<br>|
| Active Comparator: Caloric deficit<br>The investigators observed significant weight loss in the TRF group with participants reporting to consume  400 kilocalories less per day. Therefore the investigators added a caloric deficit group to control for the effects of weight loss on metabolism. Total energy expenditure was measured for one week and was used to prescribe a 400 kilocalories/day energy deficit diet to follow for two weeks. | Behavioral: Caloric restriction<br>* Follow a prescribed daily energy deficit of 400 kilocalories without altering nutrient timing<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in glucose uptake | The arterio-venous forearm balance method was used to assess skeletal muscle glucose uptake in micromoles/min. | Pre and post intervention (15 days apart). Fasted blood samples and every 10 min for 3 hours following consumption of carbohydrate + protein drink | 
| Change in branched chain amino acid uptake | The arterio-venous forearm balance method was used to assess skeletal muscle branched chain amino acid uptake in micromoles/min. | Pre and post intervention (15 days apart). Fasted blood samples and every 10 min for 3 hours following consumption of carbohydrate + protein drink | 
| Change in whole-body insulin sensitivity | The Matsuda Index was used to calculate an index of whole-body insulin sensitivity using values of fasted and postprandial glucose and insulin. Measured in arbitrary units and higher values indicates increased insulin sensitivity. All individual changes will be reported. | Pre and post intervention (15 days apart). | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in body composition | Dual-energy X-ray absorptiometry scans to assess changes in fat mass in kg | Pre and post intervention (15 days apart) | 
| Change in body composition | Dual-energy X-ray absorptiometry scans to assess changes in fat-free mass in kg | Pre and post intervention (15 days apart) | 
| Change in substrate metabolism | Rates of oxygen consumption and carbon dioxide production were measured using indirect calorimetry. These were used to calculate rates of fat and carbohydrate metabolism in grams/min. | Pre and post intervention (15 days apart). In each condition there was one measurement in the fasted state and two measurements in the postprandial state. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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chrononutrition, metabolism, body composition