The hunter-gatherer diet featured a large variation in nutrients with greater amounts of animal products and also plant foods. When agriculture transitioned about 10,000 years ago, the wide variety of foods was impossible to maintain. Instead, humans' diets consisted primarily of large quantities of the least domesticated plants, such as rice, wheat, and corn. Because dietary diversity was declining, the energy expenditure of growing crops was higher, especially in some seasons. Nutritional deficiencies began to appear in populations where the diet was based on one or two staple foods. Ancient bones show a variety of information about how the nutritional status of humans was affected by the transition to agriculture. Claire Cassidy's comparison of the skeletons of Indian hunter-gatherers from Knoll and those from Hardin Village shows that tooth decay and porotic hyperostosis are more prevalent in humans who ate agricultural diets (as cited in Wiley & Allen, 2013, p.90). Furthermore, growth failure is more severe and occurred over a longer period of time in groups that relied on the domestication and cultivation of their animals.