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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.
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.
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.
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.
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.
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.
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.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Energy Balance | Placebo Comparator | Participants will be in energy balance and consume 1.2 g/kg BW protein. They will be provided 30 g of maltodextrin following exercise. |
|
| Caloric Restriction and CHO Supp | Active Comparator | Participants will be calorie restricted to 15 kcal/kg FFM/day and consume 1.2 g/kg BW protein. They will be provided 30 g of maltodextrin following exercise. |
|
| Caloric Restriction and PRO Supp | Experimental | Participants will be calorie restricted to 15 kcal/kg FFM/day and consume 1.2 g/kg BW protein. They will be provided 30 g of whey protein following exercise. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Caloric Restriction | Other | Participants will consume 15 kcal/kg FFM/day. |
|
| Measure | Description | Time Frame |
|---|---|---|
| Change in Serum [IGF-1] (ng/mL) | Measured via ELISA | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise |
| Change in Serum [GH] (pg/mL) | Measured via ELISA | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise |
| Change in Serum [IGFBP-3] (ng/mL) | Measured via ELISA | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise |
| Change in Serum [P1NP] (pg/mL) | Measured via ELISA | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise |
| Change in Serum [CTX] (ng/mL) | Measured via ELISA | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise |
| Change in Serum [Sclerostin] (pmol/L) | Measured via ELISA | Baseline, Pre-Exercise, 0-24 Hours Post-Exercise |
| Measure | Description | Time Frame |
|---|---|---|
| Change in Body Weight (kg) | Measured via Stadiometer | Baseline and Day 4 |
| Change in Body Fat Percentage (%) | Measured via DXA and BIA |
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Baseline Inclusion Criteria:
Tested Inclusion Criteria:
- <20% body fat (men) or <30% body fat (women)
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Karsten Koehler | University of Nebraska Lincoln | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Sports and Exercise Nutrition Laboratory, Department of Nutrition and Health Sciences, Ruth Leverton Hall | Lincoln | Nebraska | 68583 | United States |
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| ID | Term |
|---|---|
| D015431 | Weight Loss |
| D013217 | Starvation |
| ID | Term |
|---|---|
| D001836 | Body Weight Changes |
| D001835 | Body Weight |
| D012816 | Signs and Symptoms |
| D013568 | Pathological Conditions, Signs and Symptoms |
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| ID | Term |
|---|---|
| D031204 | Caloric Restriction |
| D002118 | Calcium |
| D014807 | Vitamin D |
| ID | Term |
|---|---|
| D004035 | Diet Therapy |
| D044623 | Nutrition Therapy |
| D013812 | Therapeutics |
| D002149 | Energy Intake |
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| Post-Exercise Protein | Dietary Supplement | Participants will ingest 30 g of protein following exercise. |
|
| Energy Balance | Other | Participants will consume 40 kcal/kg FFM/day. |
|
| Post-Exercise Carbohydrate | Dietary Supplement | Participants will ingest 30 g of carbohydrate following exercise. |
|
| Calcium and Vitamin D | Dietary Supplement | Participants will be supplied Calcium and Vitamin D supplements throughout the study period matched to the CON condition. |
|
| Baseline and Day 4 |
| Change in Perceived Hunger (mm or %) | Measured on Visual Analog Scale within Survey | Baseline and Day 4 |
| D044342 | Malnutrition |
| D009748 | Nutrition Disorders |
| D009750 | Nutritional and Metabolic Diseases |
| D004032 |
| Diet |
| D009747 | Nutritional Physiological Phenomena |
| D000066888 | Diet, Food, and Nutrition |
| D010829 | Physiological Phenomena |
| D008673 | Metals, Alkaline Earth |
| D004602 | Elements |
| D007287 | Inorganic Chemicals |
| D008670 | Metals |
| D001779 | Blood Coagulation Factors |
| D001685 | Biological Factors |
| D012632 | Secosteroids |
| D013256 | Steroids |
| D000072473 | Fused-Ring Compounds |
| D011083 | Polycyclic Compounds |