We associate obesity with poor clinical outcomes, including in people with type 2 diabetes. Compelling evidence links obesity in early life to higher risks of diabetes and death, justifying population-wide prevention efforts. However, obesity has been associated with improved rather than poorer diabetes outcomes and we lack good evidence that weight loss prevents diabetes complications and death. Obesity in diabetes might also confer health benefits in terms of enhancing beta-cell mass and maintaining bone health. These paradoxical findings will form the basis of discussion about the therapeutic role of weight loss in diabetes.