When you eat foods that contain carbohydrates, the digestive system breaks down what can be digested into sugar, which enters the blood.
When blood sugar levels increase, your pancreas produces insulin, a hormone that encourages cells to absorb blood sugar for energy or storage.
As cells absorb blood sugar, levels in the bloodstream start to fall.
When this happens, the pancreas starts building glucagon, a hormone that signals the liver to start releasing stored sugar.
This interaction of insulin and glucagon ensures that cells throughout the body, particularly in the brain, have a steady supply of blood sugar.
Carbohydrate metabolism is important in the development of type 2 diabetes, which occurs when your body cannot make enough insulin, or cannot use the insulin it makes properly.
Type 2 diabetes generally develops gradually over a number of years, starting when muscles and other cells stop responding to insulin. This condition, known as insulin resistance, causes blood sugar and insulin levels to remain high, long after a meal. Over time, the heavy demands that are made on the insulin-making cells tire them out, and insulin production eventually stops.
Glycemic index
Carbohydrates are generally classified as simple or complex, and are described in the following:
Complex carbohydrates:
They have a more complex chemical structure, with three or more sugars linked together (oligosaccharides and polysaccharides). Many complex carb foods containing fiber, vitamins and minerals take longer to digest, which means they have a lesser impact on blood sugar, causing it to rise more slowly. But other foods called complex carbohydrates such as white bread and white potatoes contain mostly starch but little fiber or other beneficial nutrients.
Dividing carbohydrates into simple and complex, however, does not take into account the effect of carbohydrates on blood sugar and chronic disease. In order to explain how different types of carbohydrate-rich foods directly affect blood sugar, the glycemic index was developed and is considered a better way to categorize carbohydrates, especially starchy foods.
Simple carbohydrates:
These carbohydrates consist of sugars (fructose and glucose) which have a simple chemical structure, which consists of only one sugar (monosaccharide) or two sugars (disaccharide). Simple carbohydrates are easily and quickly used for energy by your body, due to their simple chemical structure, often leading to an increase in blood sugar and a faster secretion of insulin from the pancreas — which can have negative health effects.
Glycemic load
One thing a food’s glycemic index doesn’t tell you is how many carbohydrates it can digest, (total carbs excluding fiber) — it makes. That’s why researchers developed a related way to classify foods that takes into account both the amount of carbohydrates in the food, in relation to their impact on blood sugar levels. This measure is known as the glycemic load. (11,12) The glycemic load of a food is determined by multiplying its glycemic index by the number of carbohydrates that the food contains. In general, a glycemic load of 20 or higher, 11 to 19 is moderate, and 10 or below is low.
The glycemic load has been used to study whether a high glycemic load diet is associated with an increased risk of type 2 diabetes and cardiovascular events. In a large meta-analysis of 24 prospective cohort studies, researchers concluded that people who eat foods with low glycemic levels have a lower risk of developing type 2 diabetes than those who eat foods with higher glycemic levels. A similar type of meta-analysis concludes that a higher glycemic load diet is also associated with an increased risk of coronary heart disease.
