Claus Leitzmann has a PhD in biochemistry from the University of Minnesota and did research at the University of California, (with Nobel laureate Paul Boyer) and later at the Malnutrition and Anemia Center in Thailand. He was Professor of Nutrition (developing countries) at the University of Giessen, 1978-1998. He specialises in International, Wholesome and Vegetarian Nutrition and Nutrition Ecology. He has published hundreds of papers and 30 books on various aspects of nutrition.