Obesity paradox in different populations: evidence and controversies.

An inverse association between BMI and mortality has been reported in patients with coronary heart disease and heart failure. This 'obesity paradox' has recently been reported in other disease states, including stroke, hypertension, incident diabetes, atrial fibrillation, hemodialysis and transcatheter aortic valve replacement. Cardiorespiratory fitness influences the obesity paradox and this inverse association may be present only in individuals with low fitness levels. Intentional weight loss, exercise training and improving lean mass are important and should be advised to all patients. Recent studies have also explored the association between measures of central obesity and direct measures of body fat with mortality. This review will summarize the evidence, controversies and mechanisms associated with the puzzling obesity paradox.