Hi, Your grandfather might follow these instructions to keep himself free from diverticulitis attack and associated nausea 1. If he is having acidity associated nausea then he must take regular small meals with high fiber content. This will prevent acid pooling in the stomach which can cause nausea. He must also avoid spicy foods. 3. Eating more fiber. High-fiber foods, such as fresh fruits and vegetables and whole grains, soften waste material and help it pass more quickly through the colon. This reduces pressure inside the digestive tract. 4. He must be drinking plenty of fluids. Fiber works by absorbing water and increasing the soft, bulky waste in the colon. Not drinking enough liquid to can cause the increased fiber to be constipating. 5. He must do regular exercises to keep the bowel functions normal.