The Glycemic Index
The Glycemic Index measures how quickly glucose is absorbed after a person eats. That is, how high the blood glucose rises and then how quickly it returns to normal. The Glycemic Index is a method of classifying foods according to the body’s response to glucose levels in the blood. The higher the glucose response the higher the GI. 100 is the highest value, therefore High would be a response of 70 and above, intermediate between 56 to 69 and low, below 55. Sucrose has a lower GI than Glucose, which is one reason why fruit, despite being sweet, has a low to moderate GI. Fats slow down carbohydrate digestion thereby lowering GI.
The rate of glucose absorption is particularly important for people with diabetes, who benefit from limiting foods that produce too great a rise, or to sudden fall in blood glucose levels. Studies have shown that a high GI diet in combination with a low fibre intake increases the risk of Type II diabetes more than twofold. Increasing acidity in the meal can lower its GI due to the acid in food slowing down stomach emptying. Thereby slowing the rate in which carbohydrates are digested. High GI foods increase circulating insulin levels. It also raises levels of insulin-like growth factors, which are potent cancer growth stimulators.
Low GI foods may help with weight management. Fibre slows down digestion and prolongs the presence of food in the digestive tract, leading to greater insulin sensitivity and diminishing insulin release. Rapid absorption of glucose from a high glycemic diet is followed by a similar fall of blood sugar levels which stimulates overeating.
A number of factors influence the GI of the food.
GI alone may be misleading as it may not include the other healthy benefits contained within the food, for example; antioxidants, vitamins, minerals and fibre.
Another method of looking at the glycemic effect of for is to look at Glycemic Load. This is a ranking system for carbohydrate content and food portions based on the glycemic index and portion size. Some foods with a high GI would normally be eaten in smaller portions thus lowering their GL. However high GI/GL foods are associated with insulin resistance, lower concentrations of HDL (High Density Lipoproteins), Higher levels of cholesterol, and high levels of triglycerides in the blood. Also an increase in inflammation. All of which are risk factors for heart disease.
The Glycemic Index measures how quickly glucose is absorbed after a person eats. That is, how high the blood glucose rises and then how quickly it returns to normal. The Glycemic Index is a method of classifying foods according to the body’s response to glucose levels in the blood. The higher the glucose response the higher the GI. 100 is the highest value, therefore High would be a response of 70 and above, intermediate between 56 to 69 and low, below 55. Sucrose has a lower GI than Glucose, which is one reason why fruit, despite being sweet, has a low to moderate GI. Fats slow down carbohydrate digestion thereby lowering GI.
The rate of glucose absorption is particularly important for people with diabetes, who benefit from limiting foods that produce too great a rise, or to sudden fall in blood glucose levels. Studies have shown that a high GI diet in combination with a low fibre intake increases the risk of Type II diabetes more than twofold. Increasing acidity in the meal can lower its GI due to the acid in food slowing down stomach emptying. Thereby slowing the rate in which carbohydrates are digested. High GI foods increase circulating insulin levels. It also raises levels of insulin-like growth factors, which are potent cancer growth stimulators.
Low GI foods may help with weight management. Fibre slows down digestion and prolongs the presence of food in the digestive tract, leading to greater insulin sensitivity and diminishing insulin release. Rapid absorption of glucose from a high glycemic diet is followed by a similar fall of blood sugar levels which stimulates overeating.
A number of factors influence the GI of the food.
- The physical structure of the carbohydrate.
- The presence of other nutrients in the foods, for example, fat and fibre.
- Food preparation methods, for example; macaroni has a GI of 47 spaghetti 38.
- The GI of a food can also vary within the same person at different times in the day. The GI effect being greater after breakfast than after lunch. It can also vary between individuals.
GI alone may be misleading as it may not include the other healthy benefits contained within the food, for example; antioxidants, vitamins, minerals and fibre.
Another method of looking at the glycemic effect of for is to look at Glycemic Load. This is a ranking system for carbohydrate content and food portions based on the glycemic index and portion size. Some foods with a high GI would normally be eaten in smaller portions thus lowering their GL. However high GI/GL foods are associated with insulin resistance, lower concentrations of HDL (High Density Lipoproteins), Higher levels of cholesterol, and high levels of triglycerides in the blood. Also an increase in inflammation. All of which are risk factors for heart disease.
