 Diverticular or out-pouchings from our intestine. Doctors like using a tire analogy. High pressures within the gut can force the intestines to balloon out through weak spots in the intestinal wall, like an inner tube poking out through a worn tire tread. This is what they actually look like. These pockets can become inflamed and infected, and to carry the tire analogy further, can blow out, spilling fecal matter into the abdomen or bladder, and lead to death. Symptoms can range from no symptoms at all, to a little cramping and bloating, to incapacity and pain that is a medical emergency. 9 out of 10 people that died from the disease never even knew they had it. But the good news is that there may be a way to prevent the disease, but diverticular disease is the most common intestinal disorder, affecting up to 70% of people by age 60. If it's that common, though, maybe it's just an inevitable consequence of aging? No. It's a new disease. In 1907, 25 cases had been reported in the medical literature, not in 25% of people, but 25 cases, period. And they're kind of hard to miss on autopsy. A hundred years ago, in 1916, it didn't even merit mention in medical and surgical textbooks. The mystery wasn't solved until 1971. How did a disease that was almost unknown become the most common affliction of the colon in the Western world within one lifespan? Surgeons Painter and Birkitt suggested diverticulosis was a deficiency disease. A disease caused by a deficiency of fiber. In the late 1800s, roller milling was introduced, further removing fiber from grain, and we started to fill up on fiber-deficient foods like meat and sugar. A few decades of this and diverticulosis was rampant. This is what they thought was going on. Just as it would be easy to squeeze a lump of butter through a bicycle tube, it's easy to move large, soft, moist intestinal contents through the gut. In contrast, try squeezing through a lump of tar. See, when we eat fiber-deficient diets, our feces can become small and firm, and so our intestines really have to squeeze down hard to move it along. And this buildup of pressure may force out those bulges. And eventually, a low fiber diet can then sometimes lead to the colon literally rupturing itself. If this theory is true, then populations that eat high fiber diets would have low rates of diverticulosis, and that's what's been found. More than 50% of African Americans in their 50s were found to have diverticulosis, compared to less than 1% in African Africans eating traditional plant-based diets. And by less than 1%, we're talking zero out of a series of 2,000 autopsies, two out of 4,000 in Uganda. That's like a thousand times lower prevalence. What then about this newer study, concluding that a low fiber diet was not associated with diverticulosis? We'll cover that next.