CARBOHYDRATES, FAT, AND INSULIN ACTION

Insulin resistance is a common disorder and is seen in many conditions that are associated with increased risk for cardiovascular disease (e g, obesity, diabetes, hypertension, and cigarette smoking). The role o f the diet, irrespective of degree of obesity, in modulating insulin s ensitivity is uncertain. An extremely high carbohydrate-fat ratio impr oves insulin sensitivity whereas more moderate changes (40-60% carbohy drate) produce less convincing results. However, increased fasting con centrations of triglycerides and lower concentrations of high-density- lipoprotein (HDL) cholesterol have frequently been seen with these die ts, together with lower concentrations of low-density-lipoprotein (LDL ) cholesterol. High-carbohydrate diets based on foods with a low glyce mic index combined with a high dietary fiber content should be evaluat ed. Such diets may produce the desired effects while they prevent unwa nted increases in fasting triglyceride concentrations and lower HDL ch olesterol.