For the last 20 years the focus of nutritional advice has been to
reduce total fat intake and consume large amounts of carbohydrate.
However, this advice is inconsistent with many lines of evidence
indicating that unsaturated fats have beneficial metabolic effects and
reduce risk of coronary heart disease.
also shown that the large majority of carbohydrates in current
industrial diets, consisting of refined starches and sugars, have
adverse metabolic effects and increase risks of obesity, heart disease
Thus, in what appears to be an optimal diet,
most calories would come from a balance of whole grains and plant oils,
proteins would be provided by a mix of beans, nuts, fish, eggs, and
poultry, and the remaining nutritional needs would be filled by plenty
of vegetables and a few fruits.
Important considerations include
the role of dairy products, the interrelationships with physical
activity and genetic variations, the implications of our food choices on
environmental sustainability, and how we move from today’s pathological
diet to a more optimal way of eating.
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.
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.
Recorded on 12 June 2008 at the University of Edinburgh's George Square Lecture Theatre.