BioEnergetics and Metabolomics in Cystic Fibrosis

Cystic Fibrosis Inclusion Criteria: * have confirmed CF diagnosis with at least one Class I to III CFTR mutations * age ≥ 18 yrs * on a clinically-stable medical regimen for 3 wks * no intravenous or oral antibiotics for at least 3 wks prior to study visit Exclusion Criteria: * current pregnancy * unwilling or unable to discontinue enteral tube feeds for one night before the study visit, if applicable * most recent FEV1% \<40% * drug (recreational or prescription) or alcohol abuse * pacemaker or any electronic implantable device * unable to give informed consent Healthy volunteers Inclusion criteria: * 18-50 yrs of age * ambulatory status * absence of hospitalization in the previous year except for accidents Exclusion criteria: * current pregnancy * current active malignant neoplasm or history of malignancy (other than localized basal cell cancer of the skin) during the previous 5 years * current respiratory disease including asthma, chronic obstructive pulmonary disorder, or emphysema * current chronic autoimmune or pro-inflammatory disease * history of tuberculosis, HIV, or other chronic infection * previous diagnosis of type 1 or type 2 diabetes with active treatment with insulin or other glucose lowering medication * advanced (≥ stage 3) renal disease * body mass index (BMI) ≥ 30 kg/m2 * acute illness (such as a viral infection) within the past 2 weeks * current use of any prescription medications that would indicate presence of an acute or chronic medical condition that may influence study results * drug (recreational or prescription) or alcohol abuse * weight instability (± 10% body weight within the last 6 months) or current participation in weight loss or weight gain program * inability to provide informed consent.