Metabolically healthy obesity – where an individual has a Body Mass Index (BMI) of greater than 30 but does not appear to be at increased risk of the health complications usually associated with excess weight – has only been recently widely recognised by medical practitioners. As global levels of obesity continue to rise, identifying metabolically healthy obese patients could be critical for ensuring that patients are given appropriate and cost-effective treatment, say the authors of a Personal View published in The Lancet Diabetes & Endocrinology.
It is still unclear why some obese people appear to be protected from the health risks usually associated with excess fat, such as cardiovascular disease and type 2 diabetes, and no universally accepted criteria have been developed for identifying metabolically healthy obesity. The authors of this new paper outline some of the possible factors that might be used to identify the condition – including waist circumference, insulin resistance, and physical fitness – although they point out that considerably more research will be needed if the concept is to become clinically useful.
A clearer definition of the condition of metabolically healthy obesity and better understanding of the responsible mechanisms would mean that costly weight loss interventions, such as bariatric surgery, could be targeted to the most at-risk obese people. It could also potentially aid the development of drugs that protect against the problems that lead to illness and mortality among obese people (such as diabetes and high blood pressure). A small number of animal studies have suggested that certain proteins produced in the body may even protect against the harmful effects of obesity, although further research is needed to establish whether these mechanisms are effective in humans.