by [ Exchange Scheme ]
A rating system developed to help control carbohydrate intake by food substitution. The scheme was introduced by the American Diabetes Association and the U.S. Public Health Service in the 1950s as a way for diabetes to make choices in the foods they consumed based on personal preferences.
According to the scheme, diabetics who wanted to have pasta (which is high in carbohydrates) for their main course would be able to do so by reducing or eliminating the portion of other high-carbohydrate foods (such as dessert).
The Exchange Scheme was last revised in 1995 and has been largely replaced by the Glycaemic Index and Glycaemic Load systems.