Carbohydrate loading is generally recommended for endurance events lasting longer than 90 minutes. Many endurance athletes prefer foods with low glycemic indices for carbo-loading due to their minimal effect on serum glucose levels. Low glycemic foods commonly include fruits, vegetables, whole wheat pasta, and grains. Many marathoners and triathlon participants have large pasta dinners the night before the race. Since muscles also use amino acids extensively when functioning within aerobic limits, meals should also include adequate protein. Large portions before a race can, however, decrease race-day performance if the digestive system has not had the time to process the food regimen.

Answer this question based on the passage: when is carbohydrate loading recommended to be used? Let's have some stream of consciousness first.
To answer the above question, the relevant sentence is: Carbohydrate loading is generally recommended for endurance events lasting longer than 90 minutes. So, the answer is for endurance events lasting longer than 90 minutes.