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Walter C. Willett, MD, DrPH

Fredrick John Stare Professor of Epidemiology and Nutrition
Chair, Department of Nutrition
Harvard School of Public Health
Professor of Medicine, Harvard Medical School
Boston, Massachusetts

Current Research

  • Seeking to characterize the impact of diet and lifestyle on health outcomes, particularly on the risk and outcomes of breast cancer.

  • Ongoing studies are focused on the effect of meat and other protein sources on breast cancer risk and in refining the tools used to assess dietary intake in research studies.

  • Dr. Willett's research has influenced numerous health recommendations and continues to inform preventive strategies for breast cancer.

Lifestyle factors, including diet, can influence the risk of breast cancer as well as breast cancer outcomes. Understanding the association with diet and breast cancer risk is complicated by inherent challenges of nutrition-based studies that rely heavily on dietary recall. Dr. Willett pools data from many cohorts totaling 33,000 cancer cases, to examine important questions relating to diet and other lifestyle behaviors, and breast cancer risk. These include validating tools to assess nutrient intake to provide guidance for the design and analyses of future studies of diet and breast cancer.

Full Research Summary

Identifying modifiable risk factors for breast cancer is of utmost importance to reduce the incidence of breast cancer.  Dr. Willet’s current BCRF-supported research will build on analyses in the Pooling Project of Prospective Studies of Diet and Cancer (DCPP), the Life Style Validation Study (LVS) and the Growing up Today Study (GUTS), all supported BCRF. 

This year, his team will examine the relation of dietary factors to risk of specific types of breast cancer, including tumors characterized by HER2 status, histology, and stage. This will allow more powerful analyses than those conducted thus far, in which all forms of breast cancer were combined. 

In addition, they will expand the family history information in their data repository to include information on affected relatives and evaluation of familial risk with breast cancer risk. Information gained from better understanding of familial risk has the potential to personalize preventive advice.  

In addition, Dr Willett’s team will continue ongoing studies of dietary and lifestyle factors to determine relationships between weight change, health status, physical activity, pregnancy, and mammographic density as participants in the Growing Up Today Study grow into adulthood.


Dr. Walter Willett is Professor of Epidemiology and Nutrition and Chairman of the Department of Nutrition at Harvard School of Public Health and Professor of Medicine at Harvard Medical School. Dr. Willett, an American, was born in Hart, Michigan and grew up in Madison, Wisconsin, studied food science at Michigan State University, and graduated from the University of Michigan Medical School before obtaining a Doctorate in Public Health from Harvard School of Public Health. Dr. Willett has focused much of his work over the last 30 years on the development of methods, using both questionnaire and biochemical approaches, to study the effects of diet on the occurrence of major diseases. He has applied these methods starting in 1980 in the Nurses' Health Studies I and II and the Health Professionals Follow-up Study. Together, these cohorts that include nearly 300,000 men and women with repeated dietary assessments are providing the most detailed information on the long-term health consequences of food choices.

Dr. Willett has published over 1,500 articles, primarily on lifestyle risk factors for heart disease and cancer, and has written the textbook, Nutritional Epidemiology, published by Oxford University Press. He also has four books book for the general public, Eat, Drink and Be Healthy: The Harvard Medical School Guide to Healthy Eating, which has appeared on most major bestseller lists, Eat, Drink, and Weigh Less, co-authored with Mollie Katzen, The Fertility Diet, co-authored with Jorge Chavarro and Pat Skerrett, and most recently, Thinfluence, co-authored with Malissa Wood, emphasizing the powerful and surprising effect friends, family, work, and environment have on weight. Dr. Willett is the most cited nutritionist internationally and is among the five most cited persons in all fields of clinical science. He is a member of the Institute of Medicine of the National Academy of Sciences and the recipient of many national and international awards for his research.

BCRF Investigator Since


Donor Recognition

The Women's Cancer Research Fund Award

Area(s) of Focus