Over 100 million Americans suffer from high blood pressure and are at increased risk for cardiovascular disease. Evidence supports the DASH (Dietary Approaches to Stop Hypertension) dietary pattern to reduce blood pressure. DASH is rich in fruits and vegetables, legumes, lean protein, and low-fat dairy, and reduced in red meats, sweets and processed foods. The Nourish trial will look at the effect of the intervention on changes in dietary quality and blood pressure among men and women with high blood pressure. Participants who join Nourish will be asked to track what they eat and drink every day through a smartphone app and to participate in online study visits. Some participants will also receive additional support from a registered dietitian. We are doing this study to understand how technology can help adults with high blood pressure follow a heart-healthy eating plan to improve their blood pressure.