Obesity remains an important risk factor of cardiovascular and cerebrovascular diseases. However, it has been observed that increased body fat and body mass index predicted longer survival after the occurrence of a cardiovascular event. This observation has been named the obesity paradox. Initially, the term obesity paradox referred to the observation of the better outcome of cardiovascular diseases, such as heart failure and coronary heart disease, in obese patients as compared to underweight and normal-weight patients. Recently, similar, although fewer, observations confirm the occurrence of the obesity paradox in patients with acute cerebrovascular diseases. The underlying reasons for the protective effects of excessive body fat tissue against the consequences of acute cardiovascular and cerebrovascular diseases are poorly understood. The effect of preconditioning may be associated with the obesity paradox. The issue of the correlation between obesity and better survival of patients with cardiovascular and cerebrovascular diseases still remains largely unexplored. Debates for and against the obesity paradox continue.