PI left study institute.

Cystic fibrosis is an inherited disorder that causes severe damage to the lungs, digestive system, and other organs in the body. Individuals with cystic fibrosis often have poor weight gain and growth that can negatively impact health further by worsening lung function. Additionally, persons with the disease typically need more than the usual calories on a daily basis.

Most institutions estimate these patients' caloric needs using weight, age, and sex based mathematical formulae. However, numerous studies show that use of these formulae often yields inaccurate caloric values. Use of indirect calorimetry may give more accurate estimates of caloric needs in patients with cystic fibrosis.

The aim of our study is to assess the accuracy of caloric estimates generated using one such widely used mathematical formula, the Harris-Benedict equation, and to compare this calorie value with that obtained from indirect calorimetry testing in pediatric and adult patients with cystic fibrosis.

Study investigators will use the newly calculated caloric requirements in dietary counseling. Changes in weight and lung function after 3 months will be compared to participants' historical changes.

Inclusion Criteria:

• Patients with cystic fibrosis who are equal to or older than six years of age presenting to West Virginia University-Charleston Cystic Fibrosis Center for their regularly scheduled appointments/check-ups.
• Patients at the Cystic Fibrosis Center for at least 12 months.

Exclusion Criteria:

• Patients with cystic fibrosis who are younger than 6 years of age.
• Patients without cystic fibrosis.
• Patients currently pregnant.
• Cystic fibrosis patients with significant disease exacerbation (such as needing oral steroids or antibiotics, hospital admission within 30 days) or patients who currently having the flu or a serious upper respiratory infection.