Glycemic index and Load
The rate of glucose absorption is particularly important for people with diabetes who benefit from limiting foods that produce too great a rise or too sudden fall in blood glucose levels. Studies have shown that a high GI diet in combination with 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 slowing down stomach emptying, thereby slowing the rate in which carbohydrates are digested. High GI foods increase circulating insulin levels which 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.
§ GI can also vary within the same person at different times, and among different individuals. GI can also be affected by the time of day in which the food is consumed; the GI effect is greater after breakfast than after lunch.
§ GI alone may be misleading as it may not include other healthy benefits contained within the food, for example; antioxidants, vitamins, minerals and fibre.
Glycemic Load; 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 cholesterol, high levels of triglycerides in the blood, and inflammation, all of which are risk factors for heart disease.