Fos consists of a special kind of pure soluble fibre called fructo oligosaccharide fos which helps carry moisture through the digestive system this helps to keep waste soft and bulky thereby encouraging waste matter to move through the system faster and helping to ensure more regular movements fos also encourages the growth of beneficial or 39friendly39 bacteria in the large bowel colon indeed a recent study has shown that just 8g of fos daily for 2 weeks leads to a 10 fold inc