Cystic fibrosis also affects the digestive system. In a healthy person, the pancreas produces chemicals (enzymes) which pass into the gut as food leaves the stomach. These enzymes break down the fat. If you have cystic fibrosis, the pancreas doesn't produce enzymes. Without these enzymes, the fat in food isn't properly digested and it is hard to gain weight. The faeces contain an excess of fat and are oily and very smelly (BUPA, 2006). The presentation of unusual feces along with ongoing chest symptoms and failure to succeed in children are the three main factors which physicians will observe for when considering a diagnosis of cystic fibrosis.