GI refers to the glycemic index. this is a list of foods and a rating of how quickly they are absorbed. the lower the number, the more time it takes for them to be absorbed. this is important because you only want high gi foods postworkout because at this time you need to replenish your glycogen stores and keep your body out of a state of catabolism. at otehr times of the day you do not need energy quickly, so you want low gi foods so they wont just be absorbed fast and stored as fat b/c teh energy isnt used. do a search and you can find a list and ratings of each food.