Time-Restricted Eating and Muscle Hypertrophy

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

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.

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

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