Lifestyle factors are critical determinants of blood pressure levels operating against a background of genetic susceptibility. Excess body fat is a predominant cause of hypertension with additive effects of dietary salt, alcohol, and physical inactivity. Controlled trials in hypertensives show blood pressure lowering effects of supplemental potassium, fibre, n-3 fatty acids, and diets rich in fruit and vegetables and low in saturated fats. Some population studies show an inverse relationship between dietary protein and blood pressure levels. Regular coffee drinking raises blood pressure in hypertensives. The role of "stress" remains enigmatic, with "job strain" being a possible independent risk factor for hypertension.