An edible plastic composition contains at least 5 wt. % of heat-denatured protein, the heat-denatured protein mainly being a dispersion in the form of non-aggregated protein-based macrocolloidal particles having a size in the range of from 0.1 to 10 microns. It is suitable as a low calorie fat replacer in food products and for topical applications and is prepared by successive heating and concentrating steps in which an aqueous composition comprising less than 15% by weight of the water, of heat-denaturable protein is at least partly denatured and the protein concentration of the aqueous composition is at least doubled and at least part of any soluble protein is removed.The present process for instance offers the advantage of not requiring complicated apparatus, and moreover is easy to control.