Fat substitute

A fat substitute, also known as a fat replacer, is a food additive or ingredient designed to mimic the organoleptic and functional properties of triglycerides—such as mouthfeel, creaminess, and lubricity—while providing significantly fewer or zero calories. These substances are broadly categorized into carbohydrate-based (e.g., cellulose), protein-based (e.g., microparticulated whey protein), and lipid-based (e.g., sucrose polyesters like Olestra) materials. Lipid-based substitutes are often engineered to be structurally resistant to hydrolysis by pancreatic lipases, allowing them to pass through the gastrointestinal tract without being absorbed. While they are not biological targets in the therapeutic sense, they are utilized as dietary interventions to manage obesity, dyslipidemia, and cardiovascular disease by reducing overall caloric intake. Some fat substitutes, particularly Olestra, have also been investigated for therapeutic roles in sequestering lipophilic toxins like polychlorinated biphenyls (PCBs) to facilitate their excretion. However, their use is associated with notable safety concerns, including gastrointestinal side effects such as steatorrhea and the potential malabsorption of fat-soluble vitamins A, D, E, and K.

Other names

Fat replacerFat mimeticLipid substituteNon-caloric fatSucrose polyester

Fat substitutes provide the physical and sensory attributes of dietary fats (mouthfeel and flavor) without the associated caloric density; for example, sucrose polyesters like Olestra are too large and structurally complex to be recognized or cleaved by pancreatic lipase, thereby preventing the absorption of fat calories in the small intestine.