The relationship between the ingestion of poorly absorbed short-chain carbohydrates and development of functional gut symptoms is not new. The role of lactose and its failure to be hydrolysed was established more than 50 years ago. Fructose was recognised as a trigger for gut symptoms in the early 1980s, and the additive effect of sorbitol a few years later. In 1987, the effect of fructo-oligosaccharides on gas production and symptoms was first published followed shortly after later by the effects of galacto-oligosaccharides (GOS). Associated with these observations was speculation that such malabsorbed sugars might be linked to irritable bowel syndrome (IBS). Diets that restricted lactose were often applied in patients with IBS, but efficacy was limited. Reports of “fructose-free’ diets in IBS or functional bloating were very promising, but the diets used in such studies were not described. There was little uptake of such an approach. Lists of windy foods recommended being restricted in patients with functional gut symptoms included foods rich in GOS and fructans. The first report of restriction of dietary fructans (together with free fructose) as a therapy for IBS with fructose malabsorption was reported in 2006 followed by a randomised placebo-controlled rechallenge study that provided strong evidence that fructose and fructans were indeed causative in symptom genesis and presumably symptom loss with their restriction. On the basis of (a) the observed additive effects on symptoms of fructose and sorbitol or of fructose and fructans, and (b) commonality of assumed mechanisms by which the sugars induced symptoms (osmotic effects plus fermentative gas production), it was hypothesised in in 2005 that all the poorly absorbed short-chain carbohydrates be considered together (applying an acronym, FODMAPs) and that, to get maximal symptomatic benefit in IBS, restriction of all FODMAPs, not just single groups of them, will be needed. The low FODMAP diet was subsequently described and its evaluation in patients with IBS showed a high degree of efficacy. The concepts have evolved since 2005; the heterogeneity of physiological effects of FODMAP groups, the downgrading of clinical value in breath hydrogen testing, the effects on the microbiota, the degree of restriction needed for adequate symptomatic control and the key importance of reintroduction plans are examples of the maturation of this concept.