(35)To facilitate the comparison of products in different package sizes, it is appropriate to retain the requirement that the mandatory nutrition declaration should refer to 100 g or 100 ml amounts and, if appropriate, to allow additional portion-based declarations. Therefore, where food is prepacked and individual portions or consumption units are identified, a nutrition declaration per portion or per consumption unit, in addition to the expression per 100 g or per 100 ml, should be allowed. Furthermore, in order to provide comparable indications relating to portions or consumption units, the Commission should be empowered to adopt rules on the expression of the nutrition declaration per portion or per consumption unit for specific categories of food.