Publications

Abstract

For over half a century, researchers have been feeding different diets to rodents to examine the effects of macronutrients on whole body and tissue insulin action. During this period, the number of different diets and the source of macronutrients employed has grown dramatically. Due to the large heterogeneity in both the source and percentage of different macronutrients used for studies, it is not surprising that different high calorie diets do not produce the same changes in insulin action. Despite this, diverse high calorie diets continue to be employed in an attempt to generate a "generic" insulin resistance. The "high fat diet" in particular varies greatly between studies with regard to the source, complexity and ratio of dietary fat, carbohydrate and protein. This review examines the range of rodent dietary models and methods for assessing insulin action. In almost all studies reviewed rodents fed diets that had more than 45% of dietary energy as fat or simple carbohydrates had reduced whole-body insulin action compared to chow. However, different high calorie diets produced significantly different effects in liver, muscle and whole body insulin action when insulin action was measured by the hyperinsulinemic-euglycemic clamp method. Rodent dietary models remain an important tool for exploring potential mechanisms of insulin resistance but more attention needs to be given to the total macronutrient content and composition when interpreting dietary effects on insulin action.