Certain starch structures cause a portion of dietary carbohydrates to remain completely indigestible in the small intestine, resulting in zero glucose absorption.

Study: Effects of Consuming Heat-Treated Dodamssal Brown Rice Containing Resistant Starch on Glucose Metabolism in Humans

Some kinds of starch in this special rice aren't broken down in the gut, so they don't turn into sugar or raise blood glucose — the study shows this by seeing better insulin control without weight loss.

Study: The impact of starchy food structure on postprandial glycemic response and appetite: a systematic review with meta-analysis of randomized crossover trials

Some kinds of starch, like those in cooled potatoes or whole grains, aren’t broken down well in the small intestine, so less sugar enters the blood. This study shows those starches really do block sugar absorption, not just slow it down.

Study: Effects of Resistant Starch on Metabolic Markers and Gut Microbiota in Women with Metabolic Syndrome Risk Factors: A Randomized, Double-Blind, Pilot Study

Some kinds of starch aren't broken down in the small intestine, so they don't turn into glucose or get absorbed — this study used that type of starch and saw it reached the gut bacteria instead, which means it wasn't digested like regular starch.

Study: Effect of cooking and storage temperature on resistant starch in commonly consumed Indian wheat products and its effect upon blood glucose level

Some kinds of starch, especially in cooled boiled wheat, aren't broken down by the body and pass through the gut without turning into sugar, so they don't raise blood sugar. The study proved this by showing lower blood sugar when people and rats ate these cooled foods.