Failure of weight reduction to reduce mildly elevated blood pressure: a randomized trial

To determine the value of weight reduction on blood pressure, we randomly allocated 60 untreated, mildly hypertensive, obese individuals to a no-treatment control group or to a behaviourly-oriented weight loss ('diet') programme administered by professional dietitians. Behavioural techniques included self-monitoring, shaping, reinforcement and modelling. Subjects were reassessed after six months by an observer who was unaware of their study group. Fifty-four subjects (90%) completed the study. Diet subjects lost 4.1 kg and controls only 0.8 kg (P = 0.018). However, neither systolic nor diastolic blood pressures differed. The chance that we missed a clinically important diastolic difference of 6 mmHg (our pre-study target) is less than 1%. We conclude that our weight loss programme was successful in reducing weight but that weight loss is not useful in lowering blood pressure in mild, otherwise untreated hypertensives.