Diet is a key modifier of the risk of inflammatory bowel disease development and potentially a treatment option in patients with established disease. Epidemiological evidence associates a diet high in saturated fat, red meat, n-6 fatty acids and ultra-processed food with an increased risk of inflammatory bowel disease. Likewise, a diet high in fibre from fruit and vegetable and in n-3 is associated with reduced risk of development of inflammatory bowel disease. Preclinical studies with animals have associated several components of food industrialisation with the initiation of gut inflammation, mediated through mechanisms involving microbial dysbiosis and compromise of the innate immune system including the gut barrier. Nonetheless, RCT with all the aforementioned food components failed to ameliorate an active disease or maintain quiescent disease in remission. Exclusive enteral nutrition remains the only established dietary therapy in the management of active Crohn’s disease. It can be used as a primary induction therapy, in combination with other drug therapies and for pre-surgical use to optimise post-surgical outcomes. There is a lot of interest in the development of novel dietary therapies for the management of IBD, mostly Crohn’s disease. Early data showed promise for several of them but follow-up data are from RCT less promising.