Avoid very hot, cold, or sweet foods and drinks if they increase your pain.
Caffeine-free coffee and tea are fine, but avoid drinks with sugar or salt, which increase the body's water needs.
You may be asked to avoid food or drinks with caffeine for a day or two before your test.
Avoid drinks that contain caffeine or alcohol, which will cause water loss from the body.
Try to avoid hot drinks, spicy food, extremes of temperature, and bright sunlight.
It also helps to avoid food and drinks that are especially irritating, since these can delay healing.
Also, one should avoid caffeinated drinks during the 8 hours before sleeping time.
"The best thing is to avoid foods and drinks if you notice they are a problem for you."
You will also need to avoid high-calorie drinks, which add calories without nutrients.
Also avoid very cold drinks, because they can cause stomach cramps.