•AOAC 2011.25 method generally shows higher dietary fibre than AOAC 991.43 method.•Differences are mainly explained by inclusion of LMWSDF in AOAC 2011.25.•Choice of method for dietary fibre determination impacts upon dietary fibre content.•Novel AOAC methods for dietary fibre analysis urge update of food composition databases. The definition of dietary fibre was modified by Codex Alimentarius commission in 2009, and now includes low molecular weight soluble dietary fibre. This prompted the development of new methods for determination of dietary fibre, such as AOAC 2009.01 and AOAC 2011.25. We compared the dietary fibre contents of 45 different foods from six food groups, as sources of dietary fibre frequently consumed in Slovenia. Dietary fibre was determined with methods AOAC 991.43 and AOAC 2011.25, and the results were compared. Majority of results show significantly higher dietary fibres when determined using AOAC 2011.25. Differences can be explained by low molecular weight soluble dietary fibre, which is measured by AOAC 2011.25. New methods for dietary fibre determination have impacts on national food composition databases, which remain mainly based on AOAC 991.43; defining the need to update food composition databases with data that include low molecular weight soluble dietary fibre.