Rationale and design of the Optimal Macro-Nutrient Intake Heart Trial to Prevent Heart Disease (OMNI-Heart)

Background The DASH (Dietary Approaches to Stop Hypertension) diet is a carbohydrate-rich, reduced-fat diet that lowers blood pressure (BP) and LDL-cholesterol. Whether partial replacement of some carbohydrate (C) with either protein (P) or unsaturated fat (U) can further improve these and other cardiovascular (CVD) risk factors is unknown.Methods OmniHeart is a randomized, three-period, crossover feeding study designed to compare the effects on BP and blood lipids of a carbohydrate-rich diet (CARB, similar to the DASH diet) with a diet rich in protein (PROT, predominantly from nonmeat sources) and a diet rich in unsaturated fat (UNSAT, predominantly monounsaturated). Throughout feeding (run in and the three intervention periods), participants are provided with all of their meals that meet the nutrient profile of their assigned diet. Calorie intake is adjusted to maintain weight. The target sample size is 160 (50% African-American). Participants are adults, aged 30 or older, with prehypertension or Stage ...