Duration and severity of obesity is a risk factor for developing left ventricular dysfunction, manifest cardiac damage and heart failure. To fulfill the increased energy demand with excessive body weight, the organism responds by phyiologic adaptation mechanism such as an increased blood volume, and structural and functional cardiac adaptations. These adaptations result in an increased stroke volume and cardiac output at rest and during exercise. In early stages of obesity an increased cardiac load is resulting in ventricular remodelling and diastolic dysfunction. As obesity becomes chronic a progressive impairment of diastolic and systolic function ensues, and finally a development of left heart failure. Therefore, already in early stages of cardiac overload and left ventricular dysfunction a sufficient and sustainable weight reduction should be targeted avoiding an impairment of diastolic and systolic function and development of heart failure in time.