Abstract: The present invention relates to low-fat or fat-free substances which can be used as replacements for fat (i.e., fat substitutes or fat extenders), both per se as well as in the preparation of food products. Specifically, the present invention relates to gel systems which have been size reduced to mimic fat. The gel systems are based on gels which are produced from undenatured whole milk protein and carrageenan. These gels are broken and sized by shear to produce particles which are under two microns in size. Particles of this size are described as having a "fatty mouth feel" which means that the particles have a fat-like organoleptic character. The gel systems of the present invention may be used to replace some or all of the fats which are normally present in a variety of food products. The present invention also relates to processes for producing the fat substitutes and to food products containing the fat substitutes.