Same wheat, different food

Sourdough and pasta start life as the same thing. Wheat and water. One of them is on our list of foods to eat and the other is on the list to leave alone, and the difference is what happens to the wheat next.

Sourdough is fermented. Flour and water sit for a day or more while wild yeast and bacteria eat their way through it, and by the time it is baked a good part of the starch and the gluten has already been broken down by something other than you. Your blood sugar barely notices it.

Pasta is milled and extruded. Fine flour, pressed through a die, dried hard. Nothing has been pre-digested. It is a very efficient way of turning wheat into sugar in about twenty minutes, which is exactly what a bowl of it does.

Processing is the whole story here. Two foods with identical ingredients can do opposite things depending on what got to them first. Bread from a bakery that uses a starter is in. Bread from a bag that lasts a fortnight is a different food wearing the same name.