I discuss the evidence from clinical trials,prospective observational studies,and mechanistic studies that link dietary fats and carbohydrates to cardiovascular disease(CVD).This discussion is in large part derived from an American Heart Association Presidential Advisory on Dietary Fats and CVD(Sacks FM et al,Circulation 2017;136:e1-23).In summary,randomized trials that replaced saturated fat with polyunsaturated fat,mainly linoleic acid,lowered risk of CVD.The higher the quality of the individual trial,the greater the reduction in CVD.Meta-analysis of four,high quality,core trials found reduction in CVD of about 30%.Other meta-analyses that included trials that had serious problems in design or execution also found significant reduction in CVD but about 20%rather than 30%,as would be expected.The greater the reduction in saturated fat the greater the reduction in risk of CVD.In contrast,a meta-analysis of six trials that replaced saturated fat or total fat with carbohydrate did not show significant reduction in CVD.This indicates that any evaluation of a macronutrient needs to consider the replacement.