Slow Dietary Energy Release From Glucose Sources

Background and Objectives The terms rapidly digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) are useful in vitro concepts but do not fully reflect starch digestion in vivo. This review compares currently prominent in vitro classification with physiological digestive responses. Findings In humans, starch digestion continues for at least 4 h and often up to 6 h, exceeding the timeframe captured by prominent in vitro methods. Existing classifications therefore do not fully represent the temporal digestive fate of starch. A more accurate assessment requires separating the blood glucose response into an initial rapid “bell‐shaped” digestive phase and a delayed “tail”; calibrated against a standard glucose solution and quantified by integration. Conclusions Although less convenient, in vivo assessment using continuous glucose monitoring (CGM) is necessary to evaluate starch digestion within the food matrix and according to the amount consumed, despite potential overestimation of glycemic index (GI). Significance and Novelty A physiologically relevant framework is proposed consisting of: (i) readily accessible starch (RA phase), (ii) restricted digestibility starch (RD phase), and (iii) functional fiber (FF) persisting for at least 6 h. This framework provides a more meaningful classification of starch digestion for food scientists, nutritionists, and health professionals.