Low-calorie fats are actual fats whose structure ensures that they provide fewer calories to the body. For example, salatrim has very short fatty acids and very long ones. The short ones have fewer calories and the long ones are not well absorbed; the result is that the combination contributes only about five calories per gram. Similarly, caprenin is composed partly of a very long fatty acid called behenic acid, which is poorly absorbed, and partly of medium-length fatty acids that are processed differently by the body than are the longer ones. The result is that caprenin also contributes only about five calories per gram.