Diverticulitis is a common digestive disease particularly found in the large intestine. Diverticulitis develops from diverticulosis, which involves the formation of pouches (diverticula) on the outside of the colon. Diverticulitis results if one of these diverticula becomes inflamed. Patients often present with the classic triad of left lower quadrant pain, fever, and leukocytosis (an elevation of the white cell count in blood tests). Patients may also complain of nausea or diarrhea; others may be constipated. Less commonly, an individual with diverticulitis may present with right-sided abdominal pain. This may be due to the less prevalent right-sided diverticula or a very redundant sigmoid colon. The most common symptom of diverticulitis is abdominal pain. The most common sign is tenderness around the left side of the lower abdomen. If infection is the cause, then nausea, vomiting, fever, cramping, and constipation may occur as well. The severity of symptoms depends on the extent of the infection and complications. Diverticulitis may worsen throughout the first day, as it starts as small pains and/or diarrhea, and may slowly turn into vomiting and sharp pains. The development of colonic diverticulum is thought to be a result of raised intraluminal colonic pressures. The sigmoid colon has the smallest diameter of any portion of the colon, and therefore the portion which would be expected to have the highest intraluminal pressure. The claim that a lack of dietary fiber, particularly non-soluble fiber (also known in older parlance as "roughage") predisposes individuals to diverticular disease is supported within the medical literature. Foods such as seeds, nuts, and corn were, in the past, thought by many health care professionals to possibly aggravate diverticulitis. However, recent studies have found no evidence that suggests the avoidance of nuts and seeds prevents the progression of diverticulosis to an acute case of diverticulitis. Not only has this research shown that they do not appear to be aggravating the diverticulitis, but it appears that a higher intake of nuts and corn could in fact help to avoid diverticulitis in male adults.