The starch meal will provide 30g of glucose in the form of corn starch. It will be consumed in 15 minutes. They are any other food in the meal. This quantity is corresponding to what patients can ingest after a bypass surgery, because of the poor size of their stomach. C13-carbon is a natural tracer into the corn. The measure of the increase of C13-glucose in the plasma is showing the appearance of the tracer, corresponding to the starch digestion.