Effect of a Dietary Intervention on Intracellular Lipid Levels, Insulin Sensitivity, and Glycemic Control in Type 2 Diabetes

Type 2 diabetes is a disease characterized by discordance between the amount of insulin produced by pancreatic β-cells and the amount of insulin required to overcome insulin resistance in the liver and peripheral tissues. The development of insulin resistance has been strongly associated with the prolonged accumulation of lipids (fats) in the liver cells ("hepatocellular lipid") and muscle cells ("intramyocellular lipid"). Conventional pharmacologic therapeutics for type 2 diabetes, like metformin, are designed to reduce the accumulation of hepatocellular and intramyocellular lipids and, thereby, augment insulin sensitivity. Research has shown that a low-fat, plant-based diet, in which the consumption of lipids is limited, is a similarly effective therapeutic intervention for the reduction of hepatocellular and intramyocellular lipid content and the improvement of insulin sensitivity in type 2 diabetes. The purpose of this study is to compare the effects of low-fat, plant-based dietary intervention and a portion-controlled dietary intervention (compliant with current American Diabetes Association (ADA) guidelines) on hepatocellular and intramyocellular lipid content in adults with type 2 diabetes. Using a cross-over design, participants with type 2 diabetes will be randomly assigned to start with a plant-based or a portion-controlled diet for 22 weeks. The two groups will then switch to the opposite diet regimen for an additional 22 weeks. Before and after each intervention period, the investigators will measure intramuscular and liver fat content. The investigators will also assess the relationship between these variables, insulin sensitivity, and glycemic control. The investigators hypothesize that both dietary interventions will result in reductions in intramuscular and liver fat content, and that these changes will be associated with improvements in insulin sensitivity and glycemic control in individuals with type 2 diabetes. The investigators further hypothesize that the low-fat, plant-based dietary intervention will elicit greater changes in intracellular lipid concentration, compared with the portion-controlled dietary intervention.