Time-Restricted Eating and Muscle Hypertrophy

Study Overview
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Brief Summary
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The purpose is to examine the effects of time-restricted eating (TRE; consuming all calories within an 8-hour period each day) vs. normal eating (CON; consuming same kcals and protein as TRE, but during a 10-13 hr eating window each day) during 8 weeks of resistance exercise on body composition and muscle mass (whole muscle and single fiber), muscular performance, anabolic protein signaling, single muscle fiber characteristics, and the gut microbiome in well-trained young men and women.

Detailed Description
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The primary goal pertains to muscle hypertrophy (not fat loss), thus all participants will be placed in a 10% caloric surplus.

Official Title
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The Influence of 16:8 Time-Restricted Eating on Resistance Exercise-Induced Skeletal Muscle Hypertrophy

Conditions
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Muscle Hypertrophy, Healthy and Well-Trained Men and Women

Intervention / Treatment
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* Other: Time Restricted Eating
* Other: Normal Feeding
* Other: Resistance Training
* Dietary Supplement: Whey Protein


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: 18-35 years old with <25% (men) or <30% (women) body fat have experience in resistance exercise for the whole body and performed resistance exercise at least 3 times per week the last 12 months be able to perform all necessary exercises with safe technique and no pain be able to squat 1.5x (men) or 1x (women) body weight be able to bench press 1.1x (men) or 0.55x (women) body weight be on a non-specialized, mixed macronutrient diet have a lifestyle which enables a reasonably consistent 7+ hours of sleep per night be free of any current joint, musculoskeletal, and/or neuromuscular injuries Exclusion Criteria: have any known current illness, prohibitive muscular or neuromuscular problem, hypertension, cardiac, pulmonary, liver, kidney, insulin or any other metabolic disorders (e.g. Type I or Type II diabetes) are lactose intolerant or unable to consume whey protein for any reason are on any medications known to affect protein metabolism have taken antibiotics in the last 6 months cannot refrain from consuming any alcoholic beverages, nicotine, or marijuana (or derivative) for a period of 48 hours prior to data collection (pre and post testing) consume alcohol >2x per week consume any analgesic or anti-inflammatory drug(s), prescription or non-prescription, chronically or within 48 hours of data collection consume any recreational drug(s), prescription or non-prescription, legal or illegal, chronically or within 30 days of data collection consume any caffeine or food within 12 hours of data collection cannot refrain from physical exercise (outside of activities of daily living) outside of what is prescribed by the research team for the duration of the study cannot refrain from using recovery methods such as electric stimulation, hot/cold therapy, massage, chiropractic, or personal air/water devices (Normatech, etc.) have utilized any anabolic steroid, currently or in the past cannot refrain from consumption of any supplementation (creatine, multivitamin, fish oil, protein powder, BCAA, pre-workouts, etc.) outside of what is provided cannot refrain from consuming any supplemental pro or prebiotics or other items that intentionally alter the gut microbiome fail to adhere to the nutritional guidelines or miss >3 of the exercise sessions were recently pregnant, trying to become pregnant, or are currently breastfeeding

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 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: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Time Restricted Eating (16:8)<br>Participants will consume all calories within an 8 hour window each day. | Other: Time Restricted Eating<br>* Diet will be tracked and reported every day to a qualified dietitian.<br>Other: Resistance Training<br>* 8 weeks of supervised and programmed whole body resistance training, performed 4x per week<br>Dietary Supplement: Whey Protein<br>* Consumed on all exercise days.<br>|
| Active Comparator: Control<br>Participants will consume all calories within a  12 hour window each day (4 separate meals + needed snacks). | Other: Normal Feeding<br>* Diet will be tracked and reported every day to a qualified dietitian.<br>Other: Resistance Training<br>* 8 weeks of supervised and programmed whole body resistance training, performed 4x per week<br>Dietary Supplement: Whey Protein<br>* Consumed on all exercise days.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Muscle Size - Lower Body | via Ultrasound | Pre, Mid (4 weeks), and Post (8 weeks) | 
| Changes in Muscle Size - Upper Body | via Ultrasound | Pre, Mid (4 weeks), and Post (8 weeks) | 
| Changes in Fiber Type-Specific Size | Single muscle fiber analysis | Pre and Post (week 8) | 
| Changes in Body composition | via BodPod | Pre, Mid (4 weeks), and Post (8 weeks) | 
| Acute Exercise Induced Fiber Type-Specific Anabolic Signaling (Total Concentration and Phosphorylation Status) | Men only; assessed via single fiber Simple Western | Day 1 of exercise training | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Maximal Strength | 1RM on bench press, squat, and leg extension | Pre and Post (week 8) | 
| Changes in Maximal Muscular Endurance | Maximal repetitions on bench press and leg press | Pre and Post (week 8) | 
| Changes in Gut Microbiome | via stool sample | Pre, Mid (week 2, 4, 6), and Post (week 8) | 
| Changes in Fiber Type Composition | Single Fiber via SDS-PAGE | Pre and Post (week 8) | 
| Changes in Fiber Type-Specific Resting Anabolic Signaling (Total Concentration and Phosphorylation Status) | via single fiber Simple Western | Pre and Post (week 8) | 
| Changes in Mood | via Questionnaire | Weekly for duration of the intervention (8 weeks) | 
| Changes in Enjoyment of Diet | via Questionnaire | Weekly for duration of the intervention (8 weeks) | 
| Changes in Sleep (total and quality) | via Questionnaire | Weekly for duration of the intervention (8 weeks) | 
| Changes in Menstrual Cycle | via Questionnaire; women only | Pre, Mid (week 4), and post (week 8) | 
| Total Training Volume |  | After 8 weeks | 
| Nutrient Intake | Total Kcal and grams of protein, fat, and carbohydrates | Daily, starting 7 days before the study and continuing for 8 additional weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Hypertrophy, Intermittent Fasting, Time Restricted Eating, Protein Signaling, Anabolic