Abstract: One or more of hydrolysed wheat flour, soluble dietary fibre, prebiotic dietary fibre, polydextrose and soluble corn fibre are used as basic matrix-forming ingredients in an expanded food product. The matrix-forming ingredients are mixed together with water, plus a whey protein isolate or whey protein concentrate, to increase the protein content of the food. A dough is formed which is then formed into pieces which are temperature conditioned before being expanded under a vacuum caused by evaporation of moisture in the dough. All steps of the process of making the expanded food products, including any subsequent drying, is carried out at a temperature not exceeding 75° C., which advantageously allows mixing in of temperature sensitive ingredients, e.g. vitamins, pharmaceuticals, at the dough forming stage. The products have a honeycomb structure and there is no significant change in flavour or nutritional value of the ingredients caused by the process of manufacture.