Obesity and the obesity paradox in heart failure.

Obesity has reached epidemic proportions in the general population and is associated with an increased risk for the development of new-onset heart failure (HF). However, in acute and chronic HF, overweight and mild to moderate obesity is associated with substantially improved survival compared with normal weight. This phenomenon has been termed the "obesity paradox" in HF. The majority of data pertaining to the obesity paradox identifies obesity with body mass index; however, the reliability of this method has been questioned. Newer studies have explored the use of other measures of body fat and body composition, including waist circumference, waist-to-hip ratio, skinfold thickness, and bioelectrical impedance analysis of body composition. The relationship between the obesity paradox and cardiorespiratory fitness in HF is also discussed in this review, and we explore the various potential explanations for the obesity paradox and summarize the current evidence and guidelines for intentional weight loss treatments for HF in the obese population.