The aim of the present review is to examine the evidence that blood pressure may be reduced and hypertension prevented by decreasing body weight and sodium consumption. Cross-sectional and longitudinal population studies, and intervention studies in individual subjects, suggest that hypertension can be prevented by avoiding excessive weight. Children and adolescents should particularly avoid becoming overweight as this is strongly associated with hypertension in adult life. In contrast, the hypothesis that hypertension might be reduced by restricting sodium intake is less convincing. Moreover, the amount of sodium restriction needed to significantly reduce blood pressure might make it a less practical preventative measure in the struggle against hypertension than weight loss.