The Body's Response to Food Intake in Trained, Older Adults

Inclusion Criteria: All subjects must meet the following eligibility criteria: * Age range: 60 years and older * Body mass index between 20-29 kg/m2 * Weight stable (\< 2 kg weight change within last 6 months) * Non-smoking * Constant habitual activity patterns within last 3 months * Clinically normal blood profiles (specifically, normal liver and kidney function; normal complete blood count (non-anemic); fasting blood glucose \<110 mg/dl) * Not taking medications known to influence appetite or metabolism * Non-diabetic * Confirmation of acceptability of eating the study test foods (solids and fluids) Trained subjects (Recruiting 36; N-25) must meet the following eligibility criteria: * Resistive exercise training (≥ 2 times a week) based on reported physical activity levels (questionnaire) * Active fitness level (≥ 2, 30-minute aerobic exercise sessions/week) Sedentary subjects (Recruiting 36; N-25) must meet the following eligibility criteria: * Resistive exercise training (≤ 1 time a week) based on reported physical activity levels (questionnaire) * Active fitness level (≤ 2, 30-minute aerobic exercise sessions/week) Exclusion Criteria: All subjects will be excluded based on the following exclusionary criteria: * Age: \<60 years * Body mass index: outside of the 20-29 kg/m2 range * Gained or lost \> 4.5 kg within the last 6 months * Smoker (currently or within the last year) * Intermittently been involved in a diet and/or exercise program within the last 3 months * Clinically abnormal blood profiles as identified by our study physician, Arthur Rosen, MD * Taking medications (currently or within the last 3 months) known to influence appetite or metabolism * Abnormal heart function (interpreted by a cardiologist) and assessed (for study exclusion) by our study physician, Arthur Rosen, MD * Clinically diagnosed as diabetic * Study foods are found to be unacceptable for consumption by the subject * Clinically diagnosed osteoporosis Trained subjects will be excluded based on the following exclusionary criteria: * Did not perform resistive exercise training (currently or within the last 3 months) based on reported physical activity levels (questionnaire) * Perform ≤ 1, 30-minute aerobic exercise session/week (currently or within the last 3 months) based on physical activity levels questionnaire) Sedentary subjects will be excluded based on the following exclusionary criteria: * Performed resistive exercise training (currently or within the last 3 months) based on reported physical activity levels (questionnaire) * Perform \> 2, 30-minute aerobic exercise sessions/week (currently or within the last 3 months) based on physical activity levels questionnaire)