Resistance Exercise and Protein During Weight Loss

Using Resistance Exercise and Protein Consumption to Protect Bone Health During Weight Loss

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.

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