The present invention relates to a pharmaceutical composition/formulation for the prevention of diet induced obesity. More particularly, the invention relates to a composition/formulation comprising a synergistic combination of Oleoylethanolamide (OEA) and other natural ingredients can be used for treatment for obesity and its related disorders associated with fat metabolism like non-alchoholic steatohepatitis (NASH), non-alcoholic fatty liver disease (NAFLD). This can also be helpful in controlling obesity by way of maintaining body weight. The invention also provides various formulations and methods for preparing the same.