Obesity is a major health problem with increasing prevalence around the world. The World Health Organization estimates that each year, 2.8 million people die as a result of being overweight or obese. The increased mortality can mainly be attributed to obesity-associated diseases such as type 2 diabetes mellitus, cardiovascular disease, and some types of cancer. Weight reduction represents an obesity intervention strategy, which efficiently ameliorates some associated diseases.
Schmitz et al. demonstrate that upon massive and sustained weight loss in humans undergoing bariatric surgery, hepatic inflammation resolves, while, at least in a subgroup of obese individuals, adipose tissue inflammation persists for up to 12 months. Furthermore, adipocyte-autonomous insulin action only marginally improves despite massive improvements of systemic insulin-induced glucose disposal in these patients. The results highlight that even successful, long-term weight reduction does not consistently reverse the adverse, inflammatory reactions in adipose tissue that are associated with obesity and support a molecular basis of sustained increased cardiovascular risk despite weight reduction.