glycaemic index (GI)

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glycaemic index (GI)

a ranking of foods based on the extent and rate of the postprandial rise in blood glucose that they cause, compared to the response to a reference food (either glucose or white bread); the higher the GI, the greater and more rapid the rise. Intake of carbohydrate (CHO)-rich foods with lower GI has been shown to be beneficial in improving glucose control, particularly in people with type 2 diabetes. Consideration of GI may also be relevant to athletic performance. High-index CHO-rich meals have been reported to enhance the storage of muscle glycogen during recovery from prolonged exercise. On the other hand, some evidence favours consumption prior to exercise of low rather than high GI CHO-rich foods, since high GI may elicit an inappropriate surge of insulin and/or attentuate fat oxidation, leading to faster depletion of glycogen and onset of fatigue. See also carbohydrate intake guidelines for athletes.