Duocal Liquid Duocal Liquid an emulsion consisting of a blend of dried glucose syrup & refined vegetable oils. Duocal Liquid is a dietary supplement that provides a concentrated source of energy for the dietary management of conditions requiring extra calories from a combined carbohydrate & fat source. It is also useful as an energy enhancer in tube & sip feeds, or can be used as a protein free milk substitute in patients requiring protein restriction.