Walter Willett

At a glance

• Physician and nutritional epidemiologist, Fredrick John Stare Professor of Epidemiology and Nutrition at the Harvard T.H. Chan School of Public Health and professor of medicine at Harvard Medical School.
• Chaired the Department of Nutrition at the Harvard School of Public Health from 1991 to 2017 and is one of the most cited nutrition researchers in the world.
• Helped build the diet questionnaires of the Nurses’ Health Study, which has followed tens of thousands of nurses for decades; much of what we know about trans fats, whole grains, meat and heart disease comes from it.
• Wrote the popular book Eat, Drink, and Be Healthy and co-chaired the EAT-Lancet Commission (2019), which proposed a ‘planetary health diet’: mostly plants, little red meat.
• His work is largely observational: strong, consistent associations over long periods, but not randomised trials — worth remembering when reading headlines.
• Takeaway: a diet rich in vegetables, legumes, whole grains, nuts and plant oils is one of the best-supported choices for healthy ageing.