Most patients with irritable bowel syndrome (IBS) believe that diet plays a significant role in inducing IBS symptoms and desire to know what foods to avoid. It has been found that the intake of calories, carbohydrates, proteins and fat by IBS patients does not differ from that of the background population. IBS patients were found to avoid certain food items that are rich in fermentable oligo-, di- and monosacharides and polyols (FODMAPs), but they did have a high consumption of many other FODMAP-rich food items. The diet of IBS patients was found to consist of a low calcium, magnesium, phosphorus, vitamin B2 and vitamin A content. There is no consistent evidence that IBS patients suffer from food allergy, nor is there documented evidence that food intolerance plays a role in IBS symptoms. Abnormalities in gut hormones have been reported in IBS patients. As gut hormones control and regulate gastrointestinal motility and sensation, this may explain the abnormal gastrointestinal motility and visceral hypersensitivity reported in these patients. Guidance concerning food management which includes individually based restrictions of FODMAP-rich food items and individual evaluation of the effects of protein-, fat- and carbohydrate-rich/poor diets may reduce IBS symptoms.