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.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
17
Participants will consume 15 kcal/kg FFM/day.
Participants will ingest 30 g of protein following exercise.
Participants will consume 40 kcal/kg FFM/day.
Sports and Exercise Nutrition Laboratory, Department of Nutrition and Health Sciences, Ruth Leverton Hall
Lincoln, Nebraska, United States
Change in Serum [IGF-1] (ng/mL)
Measured via ELISA
Time frame: Baseline, Pre-Exercise, 0-24 Hours Post-Exercise
Change in Serum [GH] (pg/mL)
Measured via ELISA
Time frame: Baseline, Pre-Exercise, 0-24 Hours Post-Exercise
Change in Serum [IGFBP-3] (ng/mL)
Measured via ELISA
Time frame: Baseline, Pre-Exercise, 0-24 Hours Post-Exercise
Change in Serum [P1NP] (pg/mL)
Measured via ELISA
Time frame: Baseline, Pre-Exercise, 0-24 Hours Post-Exercise
Change in Serum [CTX] (ng/mL)
Measured via ELISA
Time frame: Baseline, Pre-Exercise, 0-24 Hours Post-Exercise
Change in Serum [Sclerostin] (pmol/L)
Measured via ELISA
Time frame: Baseline, Pre-Exercise, 0-24 Hours Post-Exercise
Change in Body Weight (kg)
Measured via Stadiometer
Time frame: Baseline and Day 4
Change in Body Fat Percentage (%)
Measured via DXA and BIA
Time frame: Baseline and Day 4
Change in Perceived Hunger (mm or %)
Measured on Visual Analog Scale within Survey
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Participants will ingest 30 g of carbohydrate following exercise.
Participants will be supplied Calcium and Vitamin D supplements throughout the study period matched to the CON condition.
Time frame: Baseline and Day 4