We examined the accuracy of perceived vs actual cardiometabolic risk and physical activity within the Risk Perception Attitude Framework (RPA). We analyzed baseline data from 343 young adults (23.3 ± 4.4 years) participating in a weight management clinical trial. Cardiometabolic risk factors were measured according to standard clinical procedures. A cardiometabolic risk score was created from five biomarkers according to whether or not a standard clinical risk cut point was exceeded. Physical activity was determined by ActiGraph and self-report. Perceived risk and physical activity self-efficacy were assessed by validated measures. The Proactive cluster (low perceived risk/high self-efficacy) was most accurate regarding actual vs perceived risk awareness (54%), while the Responsive cluster (high perceived risk/high self-efficacy) was the least accurate (16%). All RPA clusters underestimated their actual physical activity, self-reporting less than half the moderate-to-vigorous physical activity that was captured via accelerometry. The RPA Framework can identify young adults unlikely to be aware of their cardiometabolic risk. Given the growing prevalence of metabolic syndrome, efforts early in adulthood to increase knowledge and awareness of cardiometabolic risk, and behaviors necessary to reduce that risk, can have substantial impact on future health.