The invention provides a process for the preparation of glycols from a saccharide-containing feedstock comprising the steps of: (a) preparing a reaction mixture in a reactor vessel comprising the saccharide-containing feedstock, a solvent, a catalyst component with retro-aldol catalytic capabilities and a first hydrogenation catalyst comprising an element selected from groups 8, 9 and 10 of the periodic table; (b) supplying hydrogen gas into the reaction mixture in the reactor vessel; (c) monitoring the hydrogenation activity in the reactor vessel; (d) when the activity of the first hydrogenation catalyst declines, as indicated by the crossing of a threshold, supplying into the reaction mixture in the reactor vessel a catalyst precursor comprising one or more elements selected from groups 8, 9, 10 and 11 of the periodic table; and (e) converting the catalyst precursor in the presence of hydrogen in the reactor vessel to a second hydrogenation catalyst to supplement the declined hydrogenation activity in the reactor vessel.