Fruit can be eaten the day before the glucose tolerance test. The glucose tolerance test requires fasting for 6-8 hours, and patients are generally advised not to eat after dinner the day before. The day before the glucose tolerance test, you can eat a normal diet, including fruits, vegetables and meat can be eaten normally, after dinner the day before, you can not eat but can drink water. The morning of the glucose tolerance test, you cannot eat but you can drink a small amount of water. Patients taking medication for chronic diseases can take the glucose tolerance test after taking the medication. You should not eat during the glucose tolerance test. If you vomit after drinking the glucose water, the results will be affected, and you may need to do the test on a different day or change the glucose water to an equivalent amount of carbohydrates.