Walter C. Willett (born June 20, 1945) is an American physician and nutrition researcher. He is the Fredrick John Stare Professor of Epidemiology and Nutrition at the Harvard School of Public Health and was the chair of its department of nutrition from 1991 to 2017. He is also a professor of medicine at Harvard Medical School.Willett is the principal investigator of the second Nurses' Health Study (NHS2 or NHS II), a compilation of studies regarding the health of older women and their risk factors for major chronic diseases. He has published more than 1,500 scientific articles regarding various aspects of diet and disease and is the second most cited author in clinical medicine.Willett is perhaps best known for his 2001 book Eat, Drink, and Be Healthy and the ensuing controversy over it. The book presents nutritional information and recommendations based on what was then the consensus of nutrition scientists, and is critical of many misconceptions about diet and nutrition, including ideas presented by guidelines from American organizations such as the USDA. Willett is frequently quoted by the media in articles regarding nutrition.In 2016, Semantic Scholar AI program included Willett on its list of top ten most influential biomedical researchers. Source: Wikipedia (en)