ABSTRACT
The decline in plant fiber consumption by humans over tens of thousands of years is shown in Figure 1.1.1. According to Kliks, the author of this figure, over the past 20,000 years the human diet has changed from one based on a coarse, plant-based regimen of greens, seeds, stalks, roots, flowers, pollen, and small amounts of animal products to a more limited, often monotypic diet in which the plant foods are primarily a few cereal grains, tubers, and legumes. Even though the study of specimens of coprolite from lower Pleistocene humans has proved difficult, this coprolite has been extremely valuable in the study of human diets of civilization dating back about 10,000 years.
These specimens of coprolite showed a high consumption of fibrous plant food. In more recent history, the concept that coarse foods of plant origin help to combat constipation
goes back to Hippocrates in the 4th century
