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 to the reaction mixture in the reactor vessel; (c) monitoring the activity of the first hydrogenation catalyst; (d) preparing a second hydrogenation catalyst by contacting in a reactor a catalyst precursor comprising one or more elements selected from chromium and groups 8, 9, 10 and 11 of the periodic table with hydrazine to convert the catalyst precursor into the second hydrogenation catalyst; (e) when the hydrogenation activity declines, supplying the second hydrogenation catalyst to the reactor vessel to supplement the declined hydrogenation activity in the reactor vessel.