At the time this study was planned, there was not yet a consensus about dietary recommendations to decrease the risk of heart disease. There was considerable controversy about the efficacy of moderate changes in dietary fat, and there was very little information about the responses of women to dietary change.
The NC-167 Regional Technical Committee includes scientists experienced with dietary studies with normal humans and with various animal models. It was deemed economical and efficient to have a human study conducted with analytic expertise contributed by all members of the committee. Thus, a direct comparison of the whole diet, rather than each component as is studied in more controlled animal experiments, was planned.
Garcia, Pilar A. and Kies, Constance
"Dietary modifications designed to affect lipid metabolism,"
Research Bulletin (Iowa Agriculture and Home Economics Experiment Station): Vol. 36
, Article 1.
Available at: https://lib.dr.iastate.edu/researchbulletin/vol36/iss600/1