This study investigates whether a protein-nutrition beverage can increase muscle protein synthesis to a similar magnitude as a control beverage.

Potential participants will be screened, and if eligible, invited to participate. Body composition and physical activity level will be assessed during the initiation visit. During the trial visits, women receive a protein-nutrition beverage; muscle protein synthesis is assessed via blood analytes and muscle biopsies at rest and after exercise. Statistical analysis includes mixed model regression approach with change in muscle protein synthesis as the primary outcome.

Inclusion Criteria:

1. Older women, 65 to 75 years of age
2. At least 5 years post-menopausal
3. Body mass index (BMI) 20.00-29.99 kg/m2
4. Maintenance of habitual diet, physical activity patterns, and body weight throughout the trial
5. Low to moderate habitual physical activity ( > 3500 but < 10,000 steps/d, no structured activity)
6. In general good health (stage I hypertension allowed - 140/90) on the basis of medical history; and taking no medication other than anti-hypertensives, selective serotonin-reuptake inhibitors, and/or statins (excluding simvastatin [Zocor] and atorvastatin [Lipitor])
7. Participant understands the study procedures and signs forms providing informed consent to participate in the study and authorization for release of relevant protected health information to the study investigator.
8. Participant can consume a protein drink in the allotted time frame of 10 minutes

Exclusion Criteria:

1. History or presence of clinically important renal or gastrointestinal disorders, diabetes mellitus (glucose >126 mg/dL, fingerstick) or metabolic disease, unstable arrhythmia, angina, taking anti-diabetic, anti-inflammatory, platelet inhibitor, or anti-coagulant medications.
2. Vegan
3. Smoker
4. Overt osteoporosis and/or osteopenia and/or sarcopenia as determined by DXA
5. High physical activity or participating in regular structured exercise (> 10,000 steps/d)
6. History of allergy, sensitivity, or strong dislike towards any of the components of the study products (dairy protein)
7. Use of an investigational drug product within the last 30 days
8. Having participated in an another infusion protocol in the past year
9. Individual has a condition the PI believes would interfere with her ability to provide informed consent, comply with the study protocol, or which might confound the interpretation of the study results or put the person at undue risk
10. Subject does not understand English