Diverticulosis, which is an acquired condition marked by mucosal herniation through defects in the colonic wall, has been termed both a "disease of the 20th century" and a "disease of Western civilization" due to its increasing prevalence in modern times and its striking geographical variability. (S. Jun and N. Stollman, Epidemiology of Diverticular Disease, Best Practice & Research: Clinical Gastroenterology, 2002 Aug;16(4):529-42)
Interestingly, diverticulosis was virtually unknown prior to the 20th century, and all studies indicate that its prevalence is increasing, especially in the urban areas of Western countries. An increasing incidence also is occurring in population groups that have moved from rural or less-developed regions to industrialized centers. The low incidence of diverticulosis in the less-developed countries of Africa may be explained in part by the high fiber content of the diet in those areas. (Ralph M. Myerson, Control diverticulosis with a high-fiber diet - includes related information, Better Nutrition (1989-90), August, 1989)
Modern foods like sugars, vegetable oils, dairy products, refined grains, and even whole grains, contain much less fiber than the fruits and vegetables common in most Stone Age diets. This lower intake of high quality dietary fiber may contribute to some modern illnesses.
Origins and evolution of the Western diet: health implications for the 21st century
Loren Cordain, S Boyd Eaton, Anthony Sebastian, Neil Mann, Staffan Lindeberg, Bruce A Watkins, James H O’Keefe and Janette Brand-Miller
American Journal of Clinical Nutrition
The fiber content (15.1 g/d) (23) of the typical US diet is considerably lower than recommended values (25–30 g) (116). Refined sugars, vegetable oils, dairy products, and alcohol are devoid of fiber and constitute an average of 48.2% of the energy in the typical US diet (Table 1). Furthermore, fiber-depleted, refined grains represent 85% of the grains consumed in the United States (Table 1), and because refined grains contain 400% less fiber than do whole grains (by energy), they further dilute the total dietary fiber intake. Fresh fruit typically contains twice the amount of fiber in whole grains, and nonstarchy vegetables contain almost 8 times the amount of fiber in whole grains on an energy basis (64). Fruit and vegetables known to be consumed by hunter-gatherers also maintain considerably more fiber than do their domestic counterparts (145). Contemporary diets devoid of cereal grains, dairy products, refined oils and sugars, and processed foods have been shown to contain significantly more fiber (42.5 g/d) than either current or recommended values (159).
Once again, the displacement of fiber-rich plant foods by novel dietary staples, introduced during the Neolithic and Industrial periods, was instrumental in changing the diets that our species had traditionally consumed—a diet that would have almost always been high in fiber. Soluble fibers (those found primarily in fruit and vegetables) modestly reduce total and LDL-cholesterol concentrations beyond those achieved by a diet low in saturated fat and fiber, by slowing gastric emptying, may reduce the appetite and help to control caloric intake (171). Diets low in dietary fiber may underlie or exacerbate constipation, appendicitis, hemorrhoids, deep vein thrombosis, varicose veins, diverticulitis, hiatal hernia, and gastroesophageal reflux (172).
Some medical doctors, such as Sidney V. Haas and Harv Haakonson, have for years had much success treating their patients with diets that are lower in modern foods like grains (www.scdiet.info/main.asp, www.pecanbread.com/elainesstory.html, www.breakingtheviciouscycle.info, www.slowcarbforlife.com/science.htm ).
Unfortunately, it usually takes many years for radical scientific breakthroughs to filter down into the general medical community and spread out beyond the innovators and early adopters. So in general, the best source of dietary information today is not MD’s or nutritionists—it is anthropologists who have studied hunter-gatherers.