Several large cohort studies examining diet and health outcomes have been conducted. The Nurses’ Health Study enrolled 121,000 women in 1976 and dietary data collection started in 1980.10 The database on diet is continually updated, now every 4 years, because the food supply and composition are always changing, particularly for manufactured products like margarines and shortenings, and people’s dietary preferences are continually evolving. Intakes of different types of fatty acids were examined in relation to risk of coronary heart disease (CHD), specifically acute myocardial infarction (MI) or fatal CHD. After 14 years, ∼1000 such incident events had occurred. When carbohydrates were used for comparison and the changes in risk with increasing percentages of energy from different types of fatty acids were examined, we found that trans-fat was most strongly related to a greater risk of CHD. SFA intake was nonsignificantly related when compared calorie-for-calorie with carbohydrate. MUFAs, and more so, PUFAs (n-6, LA), were associated with a lower risk of CHD. Thus, the tradeoff of SFA versus carbohydrates appeared to be a wash in this study. The best option to reduce risk appears to be the replacement of trans-fat and some SFA with a combination of MUFAs and PUFAs. Again, as far as SFAs are concerned, after 20 years of follow-up in the Nurses’ Health Study, there was a flat dose-response relationship between SFA and CHD risk. 11