The purpose of this study is to identify the body's response to aerobic vs. resistance exercise. Throughout this study, we will examine food intake, appetite, and physical and mental well-being before, during, and after aerobic and resistance exercise.

Inclusion Criteria:

• Body mass index between 18-29 kg/m2
• Weight stable (< 4.5 kg weight change within last 6 months)
• Non-smoking
• Constant habitual activity patterns within last 3 months
• Non-diabetic
• Resistive exercise training (≥ 2 times a week) based on reported physical activity levels (questionnaire)
• Aerobic exercise training (≥ 2 times a week, 30-min sessions) based on reported physical activity levels (questionnaire)
• Confirmation of acceptability of eating the study test foods (macaroni casserole)
• Approved to participate in this study by our study physician and principle investigator

The older subjects must also meet the following eligibility criteria:

• Age range: 65 years and older
• Body fat (women: <38%; men: <28%)
• Normal resting EKG as assessed by a Cardiologist

The younger subjects must also meet the following eligibility criteria:

• Age range: 18-29 years
• Body fat (women: <28%; men: <18%)

Exclusion Criteria:

• Body mass index: outside of the 18-29 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 diagnosed as diabetic
• Did not perform resistive exercise training (currently or within the last 3 months) based on reported physical activity levels (questionnaire)
• Did not perform adequate aerobic exercise (currently or within the last 3 months) based on physical activity levels (questionnaire)
• Study food is found to be unacceptable for consumption by the subject
• Unapproved to participate in this study by our study physician and principle investigator

The older subjects:

• Age range: <65 yrs
• Body fat (women: >38%; men: >28%)
• Abnormal resting EKG (interpreted by a cardiologist) and assessed (for study exclusion) by our study physician, Arthur Rosen, MD

The younger subjects:

• Age range: outside the >29 yrs or <18 yrs
• Body fat (women: >28%; men: >18%)