Weight Loss, Starvation
Conditions
Brief summary
The purpose of this study is to determine if post-exercise protein supplementation can rescue the anabolic response of muscle and bone to resistance exercise during caloric restriction.
Detailed description
1. Preliminary Testing Prior to the study start, participants will be weighed and body composition will be determined using bioimpedance analysis. Then participants will undergo a 5RM barbell back squat exercise testing procedure. 2. Randomization Participants will proceed through each of the following conditions lasting 3 days: CON: Participants will be in energy balance and consume 1.2 g protein/kg BW/day. Participants will be provided 30 g maltodextrin post-exercise. CR+C: Participants will be restricted to 15 kcal/kg FFM/day and consume 1.2 g protein/kg BW/day. Participants will be provided 30 g maltodextrin post-exercise. CR+P: Participants will be restricted to 15 kcal/kg FFM/day and consume 1.2 g protein/kg BW/day. Participants will be provided 30 g whey protein post-exercise. 3. Diet Prescription Dietary energy intake will be controlled using clinical products, maltodextrin and whey protein isolate to meet target energy intakes. Participants will receive calcium and Vitamin D supplementation throughout the study. 4. Exercise Prescription Participants will perform one bout of 5 sets of 5 repetitions of barbell back squat exercise on the morning of Day 3 each condition. Additional exercise and intense physical activity will be prohibited. 5. Assessments Body weight and composition (DXA + BIA), fasting blood draws for assessment of metabolic and anabolic hormones and questionnaires will be conducted before and after each condition. A 24-hour serial blood draw procedure will be conducted following each workout session on each Day 3. 6. Washout Once a participant completes a study condition, participants will continue to take daily body weights at home for up to one week. Then participants will be required to wait one more week before completing their next condition during which they will resume regular diet and physical activity.
Interventions
OTHERCaloric Restriction
Participants will consume 15 kcal/kg FFM/day.
DIETARY_SUPPLEMENTPost-Exercise Protein
Participants will ingest 30 g of protein following exercise.
OTHEREnergy Balance
Participants will consume 40 kcal/kg FFM/day.
DIETARY_SUPPLEMENTPost-Exercise Carbohydrate
Participants will ingest 30 g of carbohydrate following exercise.
DIETARY_SUPPLEMENTCalcium and Vitamin D
Participants will be supplied Calcium and Vitamin D supplements throughout the study period matched to the CON condition.
Sponsors
University of Nebraska Lincoln
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
19 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
Baseline Inclusion Criteria: * Weigh at least 110 lbs * Weight-Stable (2.5 kg) within the past six months * Height-Stable (\< 0.25 inches) within the past year * 3 years of resistance training experience Tested Inclusion Criteria: \- \<20% body fat (men) or \<30% body fat (women)
Exclusion criteria
* Lactose intolerant * Pregnancy * Taking interfering medications such as steroids, thyroid or growth hormones
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Serum [CTX] (ng/mL) | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise | Measured via ELISA |
| Change in Serum [GH] (pg/mL) | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise | Measured via ELISA |
| Change in Serum [IGFBP-3] (ng/mL) | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise | Measured via ELISA |
| Change in Serum [P1NP] (pg/mL) | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise | Measured via ELISA |
| Change in Serum [Sclerostin] (pmol/L) | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise | Measured via ELISA |
| Change in Serum [IGF-1] (ng/mL) | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise | Measured via ELISA |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Body Fat Percentage (%) | Baseline and Day 4 | Measured via DXA and BIA |
| Change in Perceived Hunger (mm or %) | Baseline and Day 4 | Measured on Visual Analog Scale within Survey |
| Change in Body Weight (kg) | Baseline and Day 4 | Measured via Stadiometer |
Countries
United States
Outcome results
None listed