Is weight loss beneficial for reduction of morbidity and mortality? What is the controversy about?

The increase of obesity and type 2 diabetes on a global scale has increased the interest in how to counteract this epidemic. Improved lifestyle in general is a fundamental approach, but other remedies such as specific weight reduction or diabetes preventive drugs and surgery have also been tested. One problem to understand is what really happens after weight loss. Ongoing studies will try to address this question, such as the Swedish Obese Subjects (SOS) surgery study, the Look AHEAD (Action for Health in Diabetes) trial in the U.S. (recruiting obese type 2 diabetic patients), and the Comprehensive Rimonabant Evaluation Study of Cardiovascular End Points and Outcomes (CRESCENDO) trial (by use of rimonabant versus placebo). This is very important, since previously, several observational studies in large population-based cohorts have indicated some detrimental effects of weight loss, even after intentional weight loss, with increased morbidity and mortality rates.