Does Resistant Starch Formed by Cooling Pasta Decrease the Postprandial Glycemic Response in Type 1 Diabetes? A Randomized Single-Blind Crossover Study

Background: Carbohydrate quality and culinary processing can meaningfully alter postprandial glycemia in people with type 1 diabetes (T1D). Cooling gelatinized starch promotes retrogradation and increases resistant starch (RS), potentially attenuating postprandial glucose excursions. Objectives: We investigated whether pasta cooled after cooking (24 h at 4 °C) and reheated before consumption improves postprandial glycemia in adults with T1D without increasing hypoglycemia risk under routine insulin pump bolus-calculator dosing. Methods: In this randomized, single-blind, crossover study, 32 adults with T1D treated with continuous subcutaneous insulin infusion (CSII) consumed two standardized pasta-based meals (50 g of available carbohydrate): freshly cooked pasta and cooled/reheated pasta. Participants administered rapid-acting insulin boluses calculated by their pump bolus calculator 10 min before the meal. Interstitial glucose was recorded for 180 min using flash glucose monitoring. Results: Compared with freshly cooked pasta, cooled/reheated pasta produced lower maximum glycemia (10.7 vs. 12.6 mmol/L, p = 0.0001), lower maximum glycemic rise (2.8 vs. 4.7 mmol/L, p < 0.0001), lower incremental area under the curve (iAUC; 211.9 vs. 524.8 mmol/L × 180 min, p < 0.0001), and a shorter time-to-peak (65 vs. 125 min, p = 0.014). Resistant starch content increased after cooling (12.88 ± 0.06 vs. 8.03 ± 0.08 g/100 g). The number of hypoglycemic episodes did not differ between conditions. Conclusions: Cooling and reheating pasta therefore increased RS and attenuated postprandial glycemia in adults with T1D without increasing early postprandial hypoglycemia in the studied setting.