Is obesity a disease?

The American Medical Association's new classification for the condition is the subject of heavy controversy

Published June 22, 2013 3:00PM (EDT)

                     (<a href=''>warakorn</a> via <a href=''>Shutterstock</a>)
(warakorn via Shutterstock)

This piece originally appeared on Pacific Standard.

Pacific Standard Disease: a disordered or incorrectly functioning organ, part, structure, or system of the body resulting from the effect of genetic or developmental errors, infection, poisons, nutritional deficiency or imbalance, toxicity, or unfavorable environmental factors; illness; sickness; ailment.

“Overweight and obesity are defined as abnormal or excessive fat accumulation that presents a risk to health,” according to both the Centers for Disease Control and the World Health Organization. “A crude population measure of obesity is the body mass index (BMI), a person’s weight (in kilograms) divided by the square of his or her height (in meters). A person with a BMI of 30 or more is generally considered obese. A person with a BMI equal to or more than 25 is considered overweight.”

So is obesity a disease?

All of a sudden, the American Medical Association thinks it is; the House of Delegates, the principal policy-making body of the AMA, recently voted to officially label obesity a disease. It is interesting to note that the “vote of the AMA House of Delegates went against the conclusions of the association’s Council on Science and Public Health, which had studied the issue over the last year,” according to the New York Times. “The council said that obesity should not be considered a disease mainly because the measure usually used to define obesity, the body mass index, is simplistic and flawed.”

The body mass index or BMI is categorized as follows:

Underweight BMI < 18.5
Normal or Ideal BMI 18.5 – < 25
Overweight BMI 25 – < 30
Obese – Grade 1 (or mild)  BMI 30 – < 35
Obese – Grade 2 BMI 35 – < 40
Obese – Grade 3 (or morbid) BMI > 40

The BMI is indeed a poor measure of obesity. Because it does not take into account lean body mass such as muscle, it can overestimate obesity in certain ethnic groups while underestimating it in others. Many physically fit people, including actors and athletes with very low percentages of body fat, register as obese when judged solely by their BMI.

There are economic implications of the AMA’s decision. If everyone who has a BMI equal to or over 30 now has a disease, then doctors can get reimbursed to treat it as such. A disease that affects over one-third of the population will generate an expensive prescription to be filled. And everyone who is labeled “obese” will have a pre-existing condition, which can surely affect premiums.

But there is more at stake here than just the BMI or other obesity measures. Cardiologists are still grappling to understand a phenomenon known as the obesity paradox. In short, obesity is generally recognized as a risk factor for the development of cardiovascular disease. But many studies of patients with the disease have shown that the best survival rates occur not in the ideal body weight but in those groups that are either overweight or mildly obese—counter-intuitive, obviously, to the conventional wisdom. Dr. Carl Lavie, one of the first researchers to describe this phenomenon, has shown that the survival benefit is related to a greater percentage of body fat, not due to a misleading BMI.

And the paradox is growing. A recent meta-analysis of almost three million people around the world—one of the most comprehensive analyses to examine the relationship between mortality and BMI—found that the lowest mortality rates were not in the ideal BMI group. It was the overweight group that had the lowest mortality rate, with a statistically significant six percent reduction over the ideal group. In fact, the mortality rate of the ideal group was actually the same as the Grade 1 (or mildly obese) group. Grades 2 and 3 did show a significantly risk, but individuals in those groups represent a small fraction of the 67 percent of all Americans who are classified as either overweight or obese (though they are among the faster growing classifications). At some level of increasing weight, there is always going to be an increased risk of mortality, but where that boundary is is far from clear.

If, for argument’s sake, these study results are correct, what are the implications?

If we remove overweight and mildly obese persons from the classification of obesity (remember obesity is defined as an “abnormal or excessive fat accumulation that presents a risk to health”) there is no longer an obesity epidemic. But the incidence of diseases likes diabetes, arthritis, heart attacks, strokes, and certain cancers needs to be accounted for. Could an alternative hypothesis be that it is not simply the mass of food we ingest but the quality that makes the difference? That it is not absolute quantity but the value of what we eat which determines who we are? That it is consuming a diet based on fat and sugar substitutes, as well as too much prepared, processed, and preserved food-like substances that results in increased visceral adipose tissue (VAT) and other specific measures of fat deposition?

Perhaps the discussion about the foods we eat needs to be less about calories and more about content.

By Michael S. Fenster

MORE FROM Michael S. Fenster

Related Topics ------------------------------------------

American Medical Association Bmi Disease Obesity Pacific Standard