Hormonal Responses to a Mixed Meal in People With Cystic Fibrosis

In this exploratory study, the hormonal responses to a mixed meal will be examined in people with cystic fibrosis. The aim of this study is to find correlates with impaired glucose tolerance that is associated with this population.

Inclusion Criteria: * Diagnosed with cystic fibrosis * Aged 18 to 45 years * Males and females of any race and ethnicity * Receiving highly effective CFTR modular therapy Exclusion Criteria: * 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.