Background - Excess adiposity (overweight) is one of a number of factors which increase risk for a range of cardiometabolic diseases. Most risk reduction strategies rely on weight reduction through dietary energy restriction. However, longterm intentional weight reduction in overweight populations has proven to be very difficult to achieve. Therefore, it is important to identify strategies to reduce risk which do not necessarily rely on weight loss. Objective - To compare the effects of adding monounsaturated fat (MUFA) from macadamia nuts on coronary risk compared to usual diet in overweight adults. Design - We used a randomised controlled trial design to study the effects of maintaining usual energy intake, but manipulating dietary lipid profile in a group of 64 overweight (BMI>25), otherwise healthy, subjects. For the intervention group, energy intakes of usual (baseline) diets were calculated from multiple 3 day diet diaries, and saturated fat was replaced with MUFA to 50%E by adding macadamia nuts to the diet. Both control and intervention groups received advice on national guidelines for physical activity and adhered to the same protocol for diet diary record keeping and trial consultations. Anthropometric and clinical measures were taken at baseline and at 10 weeks. Outcomes - No significant changes in any parameters were noted for the control group over the 10 week study period. In the macadamia group, significant (p<0.05) reductions in true waist (100.0 to 97.5cm) and total cholesterol (5.38 to 5.10mmol/L), and increases in blood glucose (5.27 to 5.43mmol/L) and percentage change in brachial artery flow-mediated dilation diameters (7.77 to 10.43) were noted. No significant changes were observed for blood pressure, BMI or inflammatory markers. Conclusion - In groups where adherence to dietary energy-reduction is poor, isoenergetic interventions which address cardiometabolic risk factors other than body weight may be beneficial.