This method determines total dietary fiber (TDF) in foods and food ingredients, as defined by Codex Alimentarius. The method measures soluble and insoluble dietary fiber, including resistant starch, as well as nondigestible oligosaccharides. In this method, enzymatic digestion is used to simulate human intestinal digestion. Insoluble dietary fiber (IDF) and soluble dietary fiber that precipitates in 78% ethanol (SDFP) are separated by filtration and quantified gravimetrically. Additionally, highly soluble oligosaccharides (SDFS) are quantified by chromatographic separation. TDF is reported as the sum of the gravimetric and high-performance liquid chromatography (HPLC) results. The digestion and chromatographic conditions of this method have been modified from those of Approved Methods 32-45.01 and 32-50.01 in an attempt to better simulate human digestion and to allow for more exact quantitation (Fig. 1) (1,2).