This trial will investigate the therapeutic potential of a prebiotic supplement to improve histological parameters of NASH. In a single-blind, placebo controlled, randomized pilot trial will be conduced in individuals with liver biopsy confirmed NASH (Non-alcoholic fatty liver activity score (NAS) ≥ 5). Participants will be randomized to receive oligofructose (8 g/day for 12 weeks and 16g/day for 24 weeks) or isocaloric placebo for 9 months. The primary outcome measure is the change in liver biopsy NAS score and the secondary outcomes include changes in body weight, body composition, glucose tolerance, serum lipids, inflammatory markers, and gut microbiota.