Implementations of the disclosed subject matter provide methods for producing ethylene glycol from a carbohydrate feed which may include conditioning a heterogeneous hydrogenation catalyst by treatment with a protic acid resulting in an acid-conditioned heterogeneous hydrogenation catalyst. Next, in a reactor under hydrogenation conditions, the carbohydrate feed may be contacted with a bi-functional catalyst system comprising the acid-conditioned heterogeneous hydrogenation catalyst, and a soluble retro-Aldol catalyst. An intermediate product stream may be obtained from the reactor including ethylene glycol.