In controlled feeding studies, a low-FODMAP diet reduced IBS symptoms compared with typical diets, with changes evident within weeks.
Randomised trials comparing low-FODMAP with standard dietary advice also show benefit, though both approaches can help, and the effect is strongest when the protocol is taught well and carefully re-expanded.
Current reviews recommend low-FODMAP as a second-line strategy after basic guidance, with an emphasis on the three-phase method: restriction, reintroduction, personalisation… so you end with a diverse, tolerable diet, not a permanent elimination plan.