Disclosed is a process for producing a filler from brewer's spent grain, in particular for supplementing a sugar substitute in a foodstuff. The process contains the following steps: a) comminuting the brewer's spent grain, b) heating the brewer's spent grain, c) optionally: fermenting the brewer's spent grain, d) optionally: reducing the moisture content of the brewer's spent grain, e) optionally: mixing the brewer's spent grain, which has in particular been dried, with at least one flavor-modifying food additive, in particular with at least one sugar substitute and/or with at least one aroma. The brewer's spent grains may be withdrawn from a mash, preferably from a beer mash, particularly preferably from a barley mash. The comminuting of the brewer's spent grain in step a) may be a milling, in particular a wet milling. The reducing of the moisture content in step d) may be effected mechanically in a first substep d1) and thermally in a second substep d2). Also disclosed are a filler obtained or obtainable by
