In a new position statement, the American Association of Clinical Endocrinologists (AACE) and the American College of Endocrinology (ACE) have replaced the word “obesity” with “Adiposity-Based Chronic Disease” (ABCD).

While that sounds like a clunky switch, the authors have laid out why a simple notion should be replaced with what they call a "complications-centric" approach to the diagnosis and treatment of excess body fat (adiposity). It's more complex than something like BMI, they note.

It may be time to consider a new approach. According to the Centers for Disease Control and Prevention, obesity affects more than one-third (36.5%) of U.S. adults; that number is more than double what it was in 1990 (<15%). Obesity carries an estimated annual medical cost of $147 billion in U.S. dollars and the annual medical expenditure for people who are obese is estimated to be $1,429 higher than others. Yet, when we think of the word “obesity”, the image that comes to mind is often associated with size and appearance. In other words, the health consequences of the excess body fat, which should be front and center, are often afterthoughts. The premise of the new nomenclature is to move away from the imagery associated with the word “obesity” which tends to focus more on appearance and social acceptance, to health consequences, by using a term that puts more emphasis on the chronic diseases that result from excess body fat.

Proposed Changes: The authors propose no longer defining obesity by Body Mass Index (BMI) alone and moving to a three-pronged assessment of excess body fat:

The amount of body fat

The distribution of body fat

The physiologic (health) impact of body fat

What’s wrong with BMI? According to the AACE and ACE, the current definition of obesity (a BMI of 30 kg/m2 or higher) is one-dimensional and vague. For example, a person labeled as “overweight” by BMI alone, may have a healthier metabolic profile than someone with a lower BMI. That is because BMI cannot differentiate between fat and muscle. It also does not provide any information on muscle mass, body fat distribution, or underlying health status. This ambiguity is one reason that healthcare providers lack specific targets for intervention beyond the number on a scale. As such, the approach has largely been ineffective. While BMI is a useful screening tool for adiposity, it can't be used as a stand-alone tool for obesity diagnosis or treatment.

Why is it important to know about fat distribution? People who carry their weight in their mid-section are more prone to insulin resistance/type 2 diabetes, high cholesterol; hence, cardiovascular diseases. The same is true when fat accumulates in liver and muscle cells. Conversely, more fat accumulation in the buttocks or thighs (gluteo-femoral fat) has been shown to have a protective effect on blood sugar and cholesterol related cardiovascular diseases. There is evidence that hormones like Leptin (which controls hunger) and adiponectin (which regulates blood sugar and fatty acids) may be increased in people with gluteo-femoral fat distribution, while inflammatory cytokines are increased in those with excess abdominal fat. Body fat proportion is a useful tool for identification of disease predisposition. However, outside of the study setting, there have been no standardized testing guidelines available to healthcare providers to use in the clinical setting. That will hopefully change in the future.

Health consequences of body fat: Excess body fat (adiposity) is associated with many health consequences such as insulin resistance/type 2 diabetes, high cholesterol, and elevated blood pressure, which result in cardiovascular events like heart attack and stroke. When adiposity is identified early, preventive measures - beyond weight loss - should be initiated to monitor for commonly associated abnormalities with blood pressure, cholesterol, blood sugar and the like. The AACE and ACE vows to develop evidence based lifestyle modification protocols that healthcare providers can use to help their patients prevent serious chronic diseases.

Implementation of ABCD approach: The first step in the management of Adiposity-Based Chronic Disease (ABCD will have to catch on) is individual engagement and education. This multifaceted approach to obesity disease management will not take effect overnight. It will require a collaborative effort between patients, healthcare providers, insurance companies, and legislators. It will require development of comprehensive treatment protocols that go beyond verbal encouragement during office visits.

Studies will need to be done to show evidence of what works, so that changes can to be made at the legislative level to implement diagnostic and treatment plans that will be reimbursed by insurance companies. The AACE and ACE vow to continue the work that remains to be done, while the ABCD term lays the groundwork for this movement.