Bone grease processing is frequently used in archaeology to investigate human diet breadth because it constitutes a costly mode of lipid procurement. However, problems of equifinality often complicate the identification of this activity. This paper develops new criteria focused on morphology, the presence of micro-inclusions, and forms of damage that were derived from a bone grease rendering experiment that involved red deer(Cervus elaphus)long bones. Because they are poorly represented in a distinct experiment focused exclusively on marrow extraction, the criteria presented here appear to provide robust signatures of bone grease processing. A survey of the actualistic literature shows that certain bone processing activities, such as stewing and soup making, mostly involve coarse spongy fragments. Because these fragments are too large to be ingested, grease can be extracted from them only through heating or boiling. In contrast, bones ingested in bone meal or as flour necessitate pulverization. A high percentage of coarse fragments may therefore provide a proxy for cooking technology or, minimally, the use of fire, if other patterns are consistent with grease extraction. Given the evolutionary significance of these innovations, the criteria presented here may help to strengthen arguments about dietary shifts during the Paleolithic and later periods.