Whey Protein, Resistance Training, and Changes in Body Composition

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.

Inclusion criteria

• BMI 25-39.9
• must be 18- 30 years old
• sedentary
• no medications
• stable weight for at least 3 months

Exclusion criteria

• Tobacco/Drug user
• metabolism altering medication
• gain/lost 10lbs in the last 3 months
• current exerciser