Quick Take: The Problem With Redefining Obesity

A proposal to establish more objective criteria for defining clinical obesity aims to standardize treatment of a growing global health issue. But it may have unintended negative consequences for children, says a Duke pediatrician and expert on obesity.

The guidelines, published in January by The Lancet Commission on Clinical Obesity, call for moving away from using body mass index (BMI) as the sole factor in defining obesity. It recommends using a combination of multiple measures, such as BMI along with waist-to-hip or waist-to-height ratios, and differentiating between clinical and pre-clinical obesity to offer clearer treatment guidance for doctors and patients.

But using multiple measures to diagnose obesity may add to the stigma children already feel about their bodies, says Sarah Armstrong, M.D., an associate professor of pediatrics at the Duke School of Medicine and an affiliate of the Duke Global Health Institute.

“Asking a teenage girl with a bigger body to lift up her shirt to put a tape measurement around her waist can be an embarrassing experience,” Armstrong says. “It doesn’t help [a provider] take better care of her, and it could potentially add a negative experience to healthcare settings.”

In this Quick Take video, Armstrong acknowledges problems with using BMI alone to diagnose obesity. She says BMI is effective as a population-level indicator of people who are at increased risk for obesity-related conditions such as diabetes or cardiovascular disease. But she adds it should not be used to label individual patients as obese, in part because it does not distinguish between fat and muscle mass.

 “A person can have a bigger body, eat very healthy and be active,” she says. “As a society, we need to stop making assumptions about people based on how they look.”

Armstrong prefers a holistic approach, considering a patient’s medical history and lifestyle and meeting them where they are on ways to improve their health. At Duke, she is part of a partnership with Durham’s Parks and Recreation department to help patients incorporate more physical activity and better nutrition into their daily lives. A recent study found the program helped reduce patients’ BMI and improve overall health.  

“Some say the U.S. has a ‘sick care system’ and not a healthcare system, and that we prefer people to be sick before we offer them treatment,” she says. “What we need to do is offer people help and support to prevent diseases. To do that, we need to screen diligently, treat patients with dignity and respect and value their autonomy for how and what type of treatment they prefer to use.”