Fermenting out the bad stuff…
Some starches are good for you and some are not.
The good kind is resistant starch which survives the stomach to do good things in the intestines to help with regularity.
The bad kind converts to glucose very quickly causing your blood sugar level to spike upwards.
The slow fermentation of authentic sourdough bread increases the percentage of resistant starch by allowing the bacteria in the starter to eat away the bad starch. The result is delicious bread with an altered carbohydrate profile that aids digestion and slows conversion to glucose for a lower glycemic load.