The term ‘obesity’ is often used and sometimes it is not clear what it means. Does it refer to someone who is overweight, or has some excess weight to lose, or is it more than that? Well, there is a medical definition for obesity, as well as for the term “overweight”.
What is Overweight? In medical terminology, the word overweight is used both as a noun (as in “obesity and overweight”) and as an adjective. Such use makes it clear that overweight and obesity are part of a disease process, which will be discussed in more detail below. The medical definition of overweight is based on body mass index (BMI). BMI is measured in units of kg/m2, which means height and weight are required for the calculation. BMI calculators are readily available online, such as those from the National Heart, Lung, and Blood Institute (NHLBI). Overweight is defined as a BMI of 25.0 to 29.9 kg/m2. A normal BMI is defined as falling between 18.5 and 24.9. Having a BMI less than 18.5 classifies someone as underweight.
What is Obesity? As with overweight, the medical definition of obesity depends on the BMI calculation. To be classified as obese, a patient must have a BMI of 30.0 or higher. A BMI of 40.0 or higher is often referred to as “morbid obesity” and is recommended by national guidelines as the cut-off point for identifying very muscular individuals, who may have a high BMI due to their greater muscle weight rather than to body fat. Thus, BMI is intended to be part of a larger clinical assessment.
Why does it matter? Many studies have shown that the risk of poorer health (in teams of diseases such as cancer, cardiovascular disease, obstructive sleep apnea, diabetes, high blood pressure and others), as well as overall premature death, increases as BMI increases. And the clinical definition of obesity (BMI of 30.0 or higher) is used in many cases to determine appropriate treatment options. There are also implications for insurance coverage and what therapies are deemed medically necessary. In 2013, the American Medical Association (AMA) officially declared obesity a disease, recognizing the “enormous humanitarian and economic impact of obesity as it requires the medical care, research and education attention of other major global medical diseases.”
In 2013, the American Heart Association, American College of Cardiology, and The Obesity Society released new long-awaited obesity guidelines, which were published as the “2013 ACCF/AHA/TOS Guideline for the Management of Overweight and Obesity in Adults.” the official recognition of obesity as a chronic disease is expected not only to raise public awareness of the problem, but also to influence policy at all levels. Policymakers may feel a greater need to fund and implement obesity treatment and intervention programs, while third-party payers may be more likely to reimburse physicians and other health care professionals for the treatment and management of obesity as a recognized disease.
As for the Medicare and Medicaid Services (CMS) Centers, obesity has been categorized as a chronic disease since 2004. As of November 29, 2011, Medicare covers the cost of behavioral therapy for patients diagnosed with obesity. This may include screening with BMI and waist circumference, nutritional evaluation, and intensive behavioral interventions.