The objective of this project is to determine the effect of 9 months of progressive resistance training with daily whey protein supplements on the body composition (changes in muscle and fat) in young adults. The investigators hypothesize that those individuals who receive whey protein supplements will have larger gains in muscle and larger losses of fat tissue in response to resistance training compared to those who receive supplements of soy or carbohydrate.
Healthy men and women will be recruited to participate in 9 months of supervised resistance training (3 days/wk) and will be randomized to one of three daily supplement groups: Whey protein, soy protein, or carbohydrate control. Body weight, muscular strength and endurance, and resting blood pressure will be assessed at baseline, 3, 6 and 9 months. Body composition will be assessed at baseline, 3, 5, 7, and 9 months. A sub-sample (N = 17 per group, assessed at baseline and 9 months) will be randomly selected for muscle samples of the upper leg to determine changes in the size of muscle fibers, and chemical factors associated with muscle growth. Blood samples will be obtained from sub-sample participants to assess changes in glucose and fat metabolism, as well as other chemicals likely to promote or inhibit muscle growth. We will also assess changes in daily energy expenditure and the use of fuel to produce energy (carbohydrate, fat, protein) that may result from the intervention. We hypothesize that those individuals who receive whey protein supplements will have larger gains in muscle and larger losses of fat tissue in response to resistance training compared to those who receive supplements of soy or carbohydrate.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
85
40 g/day of whey protein will be consumed in 2 doses for 9 months (Study duration)
40 g/day of soy protein will be consumed in 2 doses for 9 months (Study duration)
40 g/day of maltodextrin will be consumed in 2 doses for 9 months (Study duration)
Energy Balance Lab, The University of Kansas
Lawrence, Kansas, United States
Body Composition
Changes in body composition will be evaluated by measuring the change in percent body fat, total fat mass, and total lean mass by DEXA.
Time frame: 9 months
24 hour energy expenditure and substrate oxidation
24hr energy expenditure and substrate oxidation will be measured by whole room indirect calorimetry
Time frame: 9 months
Muscular strength and endurance
One rep max strength will be measured on the chest and leg press.
Time frame: 9 months
Resting Metabolic Rate
Resting metabolic rate as measured by indirect calorimetry as kcal/day will be evaluated. Also, substrate oxidation (fat and carbohydrate oxidation) will be evaluated.
Time frame: 9 months
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