Protein Intake and Physical Performance

A primary aim of the current proposal is to compare the effect of daily consumption of healthy lean protein as either whey protein (2 meals per day) or whole food (25% of total daily caloric intake) consumed as 6 small meals throughout the day, one of which is consumed immediately following exercise training (within 30 min) and another 2 hours prior to going to bed at night, over a 16 week period on muscle and fat mass, cardiovascular health, aerobic fitness, glucose, insulin, blood lipids, heart rate and muscle strength in overweight men and women.

The primary purpose of this study is to examine the effects of increased healthy protein intake (25% of daily caloric intake as protein; 25% as healthy fats and oils; 50% as complex, unrefined carbohydrates) consumed as 6 small meals during the day in combination with exercise training 4 times per week, over a 16 week period in 25 overweight, but healthy males and females (30-60 yrs old). A secondary purpose is to compare the effects of consuming two of the 6 small meals during the day comprised of whole food protein source servings 20g/serving) with a matched group consuming whey protein for 2 daily protein servings (20g/serving). In the case of both groups, 1 serving will be consumed immediately following exercise \[within 30 minutes\] and 1 serving will be consumed 2 hours before going to bed. On non-exercise days, all participants will continue to consume 6 small meals per day in the same ratio of 25% lean protein, 25% healthy fats and oils, and 50% complex, unrefined carbohydrates but the groups will differ only in the composition of the last meal of the day consumed 2 hours before going to bed in which one group will consume protein (20g/serving) as whole food protein sources and the other group will consume a single serving of a whey protein supplement. The primary purpose of this study is to quantify changes in the following health outcomes at baseline and 16 weeks: total body muscle mass and fat mass (iDXA); abdominal fat mass (most highly related to cardiovascular and metabolic disease risk); blood sugar (glucose); blood lipids; insulin, aerobic fitness (assessed with a submaximal exercise test); and muscular strength (measured by 1 repetition maximum (RM) of the chest and leg press). The following additional measures will be assessed at baseline and 16 weeks: waist circumference; body weight, heart rate, blood pressure, and hunger (Visual Analog Scales).

Eligibility Criteria:
Inclusion Criteria:

* Each participant was screened prior to participating in the study using the Health and Fitness History, Physical Activity, and Physical Activity Readiness questionnaires administered by the investigators.
* Medical clearance was secured from the participant's primary care physician to verify no cardiovascular,metabolic or orthopedic issues that would prohibit them from performing the exercises for the duration of the study period
* Depending on the outcome of the health history, fitness and activity questionnaires and the physician's clearance, participants were informed of eligibility to participate in the study. A group meeting was scheduled for all eligible and interested participants to review the entire study. This process took place prior to administering any tests.

Exclusion Criteria:

* Participants were excluded if they smoked, had a whey protein intolerance, or orthopedic conditions that prohibited them from engaging in strenuous exercise