Insulin resistance (IR) and pancreatic beta-cell dysfunction are core pathophysiologic features of type 2 diabetes mellitus (T2DM). Select lifestyle and pharmacologic interventions, including weight loss, physical activity, a Mediterranean diet intervention, and hypoglycemic agents, have been shown to prevent or delay T2DM. However, dietary factors other than weight loss may also impact risk, mainly through effects to enhance insulin sensitivity, although some may also directly or indirectly impact pancreatic beta-cell function.A literature review of observational studies and randomized controlled trials (RCTs) was conducted, and the research indicates dietary factors showing promise for reducing T2DM risk include higher intakes of cereal fibers, unsaturated fatty acids, magnesium, and polyphenols (e.g. anthocyanins), while reducing dietary glycemic load, added sugars, and high-sugar beverages.While these dietary factors are mainly supported by evidence from observational studies and RCTs of surrogate markers for T2DM, they are consistent with current recommendations to emphasize consumption of whole grains, nuts, seeds, legumes, seafood, fruits, and vegetables, while limiting intakes of saturated fatty acids, refined carbohydrates, and processed meats. Additional dietary intervention RCTs are needed to assess the efficacy of these promising dietary interventions for delaying or preventing the onset of T2DM.