In this study, the investigators aim to assess the effect protein-energy enriched milk to reverse the catabolic state (weight loss, change in mid-upper arm circumference and tricpes skin fold) on the short term and failure to thrive (degree of weight recovery, change in arm circumference) one week after discharge in infants with moderate to severe bronchiolitis. The secondary short term aims are to investigate the effect on the length of hospital stay, days of oxygen support and the rate of antibiotic use. Secondary long term outcomes are the re-admission rate, the persistence of wheezing and the number of work days missed by the parents.