Walter Willett

Walter Willett is an American physician and epidemiologist at Harvard, where he chaired the Department of Nutrition for more than two decades. He leads some of the largest long-term studies of diet and health, including the Nurses' Health Study II and the Health Professionals Follow-up Study, and is among the most cited scientists in any field.

Best known for

Large cohort studies tying everyday diet to chronic disease, the Healthy Eating Plate, and co-chairing the EAT-Lancet Commission, whose 2019 planetary health diet is built mostly on plants.

Approach

Plant forward rather than strictly plant based: whole grains, vegetables, fruit, beans and nuts, with olive and other plant oils welcome and small amounts of fish, poultry and dairy allowed. He judges a diet by the quality of its foods and the type of fat, not by total fat.

Main talking points

• Swap red and processed meat for plant proteins such as beans, nuts and soy.
• The kind of fat matters more than the amount: unsaturated plant oils help, trans fats harm.
• Refined grains, added sugar and sugary drinks are among the biggest problems in modern diets.
• A diet that is healthy for people can also be good for the planet.

Books

• Eat, Drink, and Be Healthy2001
• Nutritional Epidemiology1990