 The use of log ratio transformations of dietary data can provide more accurate estimates of the relationship between dietary macronutrients and health outcomes than traditional substitution models. These transformations overcome the limitations of traditional substitution models by allowing for the simultaneous estimation of the relative importance of each macronutrient and the absolute effect of total energy intake. Additionally, the log ratio transformation allows for the interpretation of the results in terms of the relative contribution of each macronutrient to the overall health outcome. This article was authored by Maria Lea Correlate.