Update on obesity, the obesity paradox, and obesity management in heart failure

Obesity is a major public health challenge worldwide. It is costly, predisposes to many cardiovascular (CV) diseases (CVD), is increasing at an alarming rate, and disproportionately affects people of low-socioeconomic status. It has a myriad of deleterious effects on the body, particularly on the CV system. Obesity is a major risk factor for heart failure (HF) and highly prevalent in this population, particularly in those with HF with preserved ejection fraction (HFpEF), to the extent that an obesity HFpEF phenotype has been proposed in the literature. However, once HF is developed, an obesity paradox exists where those with obesity have better short- and mid-term survival than normal or underweight individuals. It may be argued that excess energy reserve, younger patient population, higher tolerability of HF therapy and better nutritional status may account for at least part of the obesity paradox. Furthermore, body mass index (BMI) may not be an accurate measure of body composition, especially in HF, where there is an excess volume status. BMI also fails to delineate fat-free mass and its components, which is a better predictor of functional capacity and cardiorespiratory fitness (CRF), which particularly is increasingly being recognized as a risk modifier in both healthy individuals and in persons with comorbidities, particularly in HF. Notably, when CRF is accounted for, the obesity paradox disappears, suggesting that improving CRF might represent a therapeutic target with greater importance than changes in body weight in the setting of HF.