This study seems to show that sugar-sweetened beverages are positively correlated with insulin resistance while diet soda does not have that same association:

This study seems to show that sugar-sweetened beverages are positively correlated with insulin resistance while diet soda does not have that same association: http://jn.nutrition.org/content/146/12/2544.short http://jn.nutrition.org/content/146/12/2544.short Sugar-Sweetened Beverage but Not Diet Soda Consumption Is Positively Associated with Progression of Insulin Resistance and Prediabetes From the footnotes on the link given: - Supported by the NIH/National Heart, Lung, and Blood Institute’s Framingham Heart Study (contract N01-HC-25195), the Boston University School of Medicine, and the USDA (USDA agreement 58-1950-0-014 - Author disclosures: J Ma, PF Jacques, JB Meigs, CS Fox, GT Rogers, CE Smith, A Hruby, E Saltzman, and NM McKeown, no conflicts of interest