This cross-sectional study from the German Diabetes Study investigated how replacing dietary carbohydrates with fats or proteins—while keeping total energy intake constant—affects fat distribution and liver fat in individuals recently diagnosed with type 1 (T1D) and type 2 diabetes (T2D). Using MRI and MR spectroscopy, researchers measured subcutaneous (SAT) and visceral adipose tissue (VAT) volumes, as well as hepatic lipid (HL) content, in 137 T1D and 170 T2D participants. Dietary intake was assessed with a validated food frequency questionnaire, and analyses accounted for macronutrient quality, such as polyunsaturated (PUFA) vs. saturated fatty acids (SFA), and plant- vs. animal-based protein.
Key findings:
In T1D, replacing carbohydrates with protein increased SAT volume; plant-based protein was linked to less SAT, while animal protein was linked to more.
In T2D, replacing carbohydrates with PUFA was associated with lower VAT and HL content, while replacing with SFA increased HL.
Substituting higher-glycemic index (GI) carbs with plant-based protein reduced HL content, while replacement with certain SFAs raised it.
Macronutrient quality—particularly PUFA and plant-based protein—was more important than macronutrient type for favorable fat distribution and liver health in T2D.