People fail to realize that the things we call "food" today are seriousel;y lacking in any nutritional value. Humans did not evolve eating campbell's soup and vegetables or chicken fried steak. We evolved literally eating the world around us. Now that people have a craving or need for the nutrients in clay, we're all stymied. mystified..can't fathom why anyone would want to eat nutrient rich dirt. uh..maybe because the daily diet of humans today is the equivlant of eating paper and salt formed in the shape of food. Clay is nutrient rich in ways "food" is not. by the time veggies reach the grocer they've lost most of thier nutritional value. Same with meat. when the body is low on a nutrient it needs to sustaion itself people experience cravings. and you'll eat what you can until that craving is sated. cravings are your body's way of saying "try that there maybe it has the vitamin i don't have."