Resistant starch type 2 improves insulin sensitivity after lunch in healthy adults, as evidenced by lower insulin levels at 300 minutes post-breakfast despite equivalent glucose concentrations, suggesting a delayed 'second meal effect' mediated by gut fermentation.

When resistant starch reaches the colon, gut bacteria break it down into short-chain fatty acids. These fatty acids travel to the liver and tell it to make less glucose. They also signal fat cells to stop storing fat and start burning it instead. This means the body uses more fat and less sugar for energy, so when the next meal comes, the pancreas doesn't need to release as much insulin to keep blood sugar normal.