When people eat a food containing carbohydrates, the digestive system breaks down the digestible ones into sugar, which enters the blood.
As blood sugar levels rise, the pancreas produces insulin, a hormone that prompts cells to absorb blood sugar for energy or storage.
As cells absorb blood sugar, levels in the bloodstream begin to fall.
When this happens, the pancreas start making glucagon, a hormone that signals the liver to start releasing stored sugar.
This interplay of insulin and glucagon ensure that cells throughout the body, and especially in the brain, have a steady supply of blood sugar.
Carbohydrate metabolism is important in the development of type 2 diabetes, which occurs when the body can’t make enough insulin or can’t properly use the insulin it makes.
Type 2 diabetes usually develops gradually over a number of years, beginning when muscle and other cells stop responding to insulin. This condition, known as insulin resistance, causes blood sugar and insulin levels to stay high long after eating. Over time, the heavy demands made on the insulin-making cells wears them out, and insulin production eventually stops.