Obesity adversely affects many cardiovascular disease (CVD) risk factors and increases the risk of most CVD, including heart failure (HF). HF is markedly increased in the setting of obesity. However, obese patients with HF have a better prognosis than lean patients with HF, which has been termed the obesity paradox . Therefore, the role of weight loss, which generally improves ventricular structure, systolic and diastolic ventricular function, and New York Heart Association functional class in HF, remains controversial. This article discusses the pros and cons of weight loss and differentiates purposeful (healthy) from nonpurposeful (unhealthy) weight loss.