Cystic fibrosis (CF) is known principally for its pulmonary consequences. However, for most individuals with CF, the earliest manifestations are not pulmonary, but gastro-intestinal. Many children experience growth failure. Chronic gut inflammation also develops. Research has also established that lung function scores are significantly correlated with Body Mass Index (BMI) and weight percentile in CF. Therefore, interventions to improve the gastro-intestinal dimension of CF in early childhood have the potential to ameliorate the course of the disease over the life span of the patient. Both Cochrane Database reviews and a recent review commissioned by the Cystic Fibrosis Foundation found only fair evidence for current nutritional guidelines.Therefore, there is a pressing need for a treatment for CF growth failure that is more effective and less invasive than current treatments.