Hormonal Responses to a Mixed Meal in People With Cystic Fibrosis

Who May Qualify: - Diagnosed with cystic fibrosis - Aged 18 to 45 years - Males and females of any race and ethnicity - Receiving highly effective CFTR modular therapy Who Should NOT Join This Trial: - Transplant recipient - Acute lung function decline or exacerbation within the last 3 months - Use of systemic glucocorticoids - Pregnancy - Known liver disease that would be expected to significantly impact metabolic variable as interpreted by a study doctor - The presence of any other disease or condition, as interpreted by any one of the study doctors, that would be expected to confound the responses to liquid mixed meal or make participation in the study dangerous to the individual - People who are cognitively impaired - People who do not speak English - For CFRD patients, a daily insulin requirement that exceeds 0.8 U/kg/day - Any prior history of diabetic ketoacidosis. Always talk to your doctor about whether this trial is right for you.