Willett joined the Harvard team in 1977 and began devising a study of dietary intake in the same population. In 1980, Willett launched a massive ongoing survey of the diet and health of the nurses, who were aged 34 to 59 at the time. He has since added 52,000 male health care professionals in 1986 and 116,000 more nurses aged 25 to 42 in 1989. Without the progress in computerized information, we would have been awash in data by now. We've compared ethnic groups in their homelands with those who migrated to other countries and found that the migrants tend to develop the same health profile as other residents of their adopted countries.
Evolutionary factors are interwoven with our individual and cultural life-styles.
In paleolithic times, humans fashioned a diet sufficient to survive through reproductive age, not to survive cancer at age 65 and sustain health into their 80s. The ability desired back then was to be physically strong enough to hunt animals and ward off predators. The ability to store fat during times of famine was also a great biological advantage. We are designed to withstand a starvation diet, yet we now find food abundant and industry trying to get us to eat even more. Willett upset the US Department of Agriculture's apple cart by overturning its 1992 food pyramid, a guide to daily food choices.