In recent years, new and redesigned ingredients have been introduced as fat substitutes and replacers. A fat replacer is an ingredient that replaces some or all of the functions of fat and may or may not provide nutritional value. A fat substitute is an ingredient that replaces all the functions of fat without any energy contribution. Currently available fat replacers are fat mimics (also called mimetics) or fat analogs. Fat mimics are based on carbohydrate, protein, and/or fat and have energy values from 0 to 38 kJ/g (0-9 kcal/g). Fat analogs have the characteristics of fat but have less energy. Because no one ingredient replaces all the functions of fat, most reduced-fat foods are formulated with a combination of ingredients and processes that affect both fat and energy content. Each formula must be evaluated for its total energy value; additionally, once acceptability and long-term use patterns of these reformulated products are established, their effect on energy intake must also be evaluated.