Effect of Caloric Restriction and Protein Intake on Metabolism and Anabolic Sensitivity
Condition: Weight Loss; Starvation
MeSH terms: Starvation; Weight Loss
Study type: Interventional

Summary: 
      The purpose of this study is to determine if an increased protein intake can attenuate the
      suppression of metabolic and anabolic hormones during caloric restriction
    

Detailed description: 
      1. Preliminary testing

           Prior to the study start, participants will be weighed and body composition will be
           determined using calipermetry (7 sites) and bioelectrical impedance. Peak oxygen uptake
           (VO2peak) will be assessed using an incremental exercise test on a bicycle ergometer.

        2. Randomization

           Participants will proceed through each of the following conditions lasting 5 days:

           CR-LP: Participants will be restricted to 30 kcal/kg FFM/day and protein intake will be
           low (0.8 g/kg BW/day).

           CR-HP: Participants will be restricted to 30 kcal/kg FFM/day and protein intake will be
           high (1.7 g/kg BW/day).

           CON: Participants will be in energy balance and consume 1.7 g protein/kg BW/day.

        3. Diet Prescription

           Dietary energy intake will be controlled using clinical products and maltodextrin to
           meet target energy intakes. Participants will received calcium and Vitamin D
           supplementation throughout the study.

        4. Exercise Prescription

           During all conditions, participants will conduct daily supervised exercise on a bicycle
           ergometer at an exercise intensity of 60% VO2peak. Exercise duration will be adjusted
           individually such that exercise energy expenditure will amount to 15 kcal/kg FFM/day.
           Additional exercise and intense physical activity will be prohibited.

        5. Assessments

           The following assessments will be conducted prior to the start of each condition as well
           as upon completion of each condition: body weight and composition (impedance), fasting
           blood draw for assessment of metabolic and anabolic hormones, resting metabolic rate,
           aerobic fitness (VO2peak), and questionnaires.

        6. Washout

      Once a participant has completed a study condition, participant will be allowed a washout of
      at least 14 days to allow protein balance to return to baseline (Hoffer & Forse, 1990).
      During this time, participants will resume their regular diet and physical activity.
    

Intervention name(s): Caloric Restriction; Protein; Exercise; Calcium and Vitamin D; Maltodextrin
Intervention type(s): Other; Other; Other; Dietary Supplement; Other
Intervention description(s): Participants will consume 30 kcal/kg FFM/day.; Participants will consume 1.7 g protein/kg BW/day.; Participants will conduct aerobic exercise designed to expend 15 kcal/kg FFM/day; Participants will be provided calcium and vitamin D supplement in order to maintain calcium and Vitamin D intake constant across all study arms; Participants will be provided with maltodextrin to supplement the liquid diet in order to meet caloric needs within each study arm
Intervention MeSH terms: Vitamin D; Calcium
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Prevention