Nutrition/calories is a huge thing for people with CF. Most CFers cant absorb fat so they need help in digesting it by taking enzymes. Because they cant absorb fat....they need a supplement for Vitamins A, D, E, K since those get abosrbed with fat. A CFers body needs much more nutrition and calories to say healthy than someone without CF. This is due to a few things. We often fight lung infections, burn off calories just from coughing & doing the treatments needed to keep our lungs clear. I am not sure how detailed U need, but this is the basics. Many of us in addition to eating will drink protein shakes which helps with the nutritional value of our diet & give us extra calories. In some cases people have feeding tubes inserted directly into their stomachs so during the times they cant/wont eat they care getting the extra help they need in nutrition.