None listed
Conditions
Brief summary
Our primary objective is to determine the effect of 5 days of dietary energy restriction (i.e. ~30 vs. the normal energy balance of ~45kcal/kg FFM/day) on muscle myofibrillar fractional synthetic rate (FSR; directly measured muscle protein synthesis) at rest as measured by primed constant infusion of ring-[13C6]phenylalanine. Our secondary objectives involve examining whether the anabolic stimulus of protein ingestion and resistance exercise will significantly increase FSR (post-exercise FSR). If an exercise plus nutrition intervention rescues the deleterious effect of a hypocaloric diet on muscle FSR this will provide novel and practical information for effective weight management in which fat mass can be reduced without loss of muscle mass.
Interventions
Trial B - Subjects will arrived after 5 days of controlled energy deficit diet (30 kcal/kg fat free mass (FFM) per day). All diets will be prepared by a specialized team and provided as pre-packaged meals, adherence to diet will be monitored via a check-list filled by participants. Tracer intravenous administration (L-ring-13C6 Phe) will start upon subject arrival and continue during 3 h for measurement of resting fractional synthetic rate (FSR) in calorie restriction diet intervention. Thereaft
Trial B - Subjects will arrived after 5 days of controlled energy deficit diet (30 kcal/kg fat free mass (FFM) per day). All diets will be prepared by a specialized team and provided as pre-packaged meals, adherence to diet will be monitored via a check-list filled by participants. Tracer intravenous administration (L-ring-13C6 Phe) will start upon subject arrival and continue during 3 h for measurement of resting fractional synthetic rate (FSR) in calorie restriction diet intervention. Thereafter, subjects will undertake a resistance exercise bout (leg press, 6 sets, 8 reps, 80% 1 repetition maximum, 3 min rest between sets). In this trial subjects will ingest a 0 (placebo), 15 or 30 g of Whey Protein in liquied form (500 ml) immediately after the exercise and FSR will be measured between 1 and 4 h post exercise for determining the muscle anabolic response to resistance exercise after 5 days of a calorie restriction diet. Trials C & D -Subjects will arrived after 5 days of controlled energy deficit diet (30 kcal/kg fat free mass (FFM) per day). Ring-13C6 Phe infusion will begin prior to resistance exercise. At the completion of exercise, subjects will ingest either 0 (placebo), 15 or 30 g of Whey Protein in liquid form (500 ml). FSR will be measured between 1 and 4 h post exercise for determining the response after exercise to either 0, 15 or 30g of WP after 5 days of a calorie restriction diet. The difference between trial B and C & D is that trial B incorporates measurement of resting FSR prior to exercise, whereas trial C and D do not incorporate a period of resting FSR measurement. After exercise all the trials are essentially the same but the drinks will be randomized to contain either 0, 15 or 30 g of protein. All participants will undertake all trials. The washout period between trials is 9 days.
Sponsors
RMIT University
Study design
Allocation
Randomised controlled trial
Primary purpose
Treatment
Eligibility
Sex/Gender
All
Age
18 Years to 35 Years
Healthy volunteers
Yes
Inclusion criteria
All subjects must comply with the following inclusion criteria: 1) Healthy and physically active (as determined by medical and activity questionnaire) 2) Having given informed consent
Exclusion criteria
Subjects representing one or more of the following criteria are excluded from participation in the study. 1) Exhibiting health risk factors as identified on the health screening questionnaire 2) Having any identified metabolic or intestinal disorders 3) Tobacco use 4) Aspirin use in the four days prior to the experimental trial 5) Consumption of prescription medications or any performance enhancing agent 6) Inability to endure the strenuous exercise bouts e.g. injuries 7) Alcohol intake during the 48 hours prior to each of the testing days 8) Currently participating or having participated in another clinical trial during the last 4 weeks prior to the beginning of this study 9) Have given blood in the last three weeks 10) Verbal confirmation that they have used a substance on the WADA banned list within the last year
Outcome results
None listed