It is accepted nowadays that dietary fiber is an important constituent of the diet. There is growing evidence that the low fiber Western diets and the low consumption of whole grain products are important factors in several common diseases of the large bowel. Cereal fiber differs from that present in vegetables and fruit. A low intake of cereal fiber has been implicated in cancer of the large bowel, diverticular disease of the colon and coronary heart disease. High fiber diets are often prescribed for diabetes. Although fiber consumption by British and American consumers has decreased over the past century, consumption of whole wheat breads and fiber-rich breakfast cereals has received new attention during the past ten years.