The term 'ERSATZ FAT' refers to a type of fat substitute. The two crossword solutions for this term are 'OLEAN' (5 letters) and 'OLESTRA' (7 letters). Olean is a brand name for a fat substitute made from olestra, which is a synthetic fat molecule created by Procter & Gamble. Olestra is used in many processed foods as a fat substitute, and it has been approved by the FDA for use in the United States since 1996.