The Impact of Carbohydrate Quality on Insulin Dose in Diabetes Mellitus Type 2: The Role of Glycemic Index, Load, and Macronutrient Composition

Carbohydrates are the focus of dietary management for type 2 diabetes mellitus (T2DM); however, we need to better understand the relative influence of related dietary factors on glycemic control. This analysis explores how glycemic index (GI), glycemic load (GL), total calories, and macronutrient composition, including carbohydrate type, affect insulin dose.We monitored fourteen participants with insulin-treated T2DM for insulin dose adjustments during three types of diet: baseline, whole food, plant-based, and two phases of Dietary Approach to Stop Hypertension. Linear mixed models were used to assess the contribution of each factor. A one-unit increase in GI was associated with a 1.056 unit increase in insulin dose (β = 1.056, 95% CI: 0.138–1.965, p = 0.0242), GL showed no significant association. Consistent with GI, higher fiber intake was negatively associated with insulin dose (β=-1.479, 95% CI: -1.996 to -0.960, p < 0.001) whereas a higher percentage of calories from added sugar was positively associated with insulin dose (β = 2.073, 95% CI: 0.52–3.627, p = 0.01). Notably, a higher percentage of calories from carbohydrates was negatively associated with insulin dose (β=-0.69, 95% CI: -1.066 to -0.313, p < 0.001).These findings suggest that quality of carbohydrates, rather than total quantity, may be more critical to insulin requirements in T2DM management.