Of even greater concern is the fact that obesity turns out to be very difficult to delineate. It is often defined in terms of body mass index, or BMI. BMI equals body mass divided by the square of height. An adult with a BMI of 18 to 25 is often considered to be normal weight. Between 25 and 30 is overweight. And over 30 is considered obese. Obesity, in turn, can be divided into moderately obese (30 to 35), severely obese (35 to 40), and very severely obese (over 40).
A hearty appetite generally indicates health and may even suggest that a person knows how to enjoy life.
While such numerical standards seem straightforward, they are not. Obesity is probably less a matter of weight than body fat . Some people with a high BMI are in fact extremely fit, while others with a low BMI may be in poor shape. For example, many collegiate and professional football players qualify as obese, though their percentage body fat is low. By BMI, Dwayne "The Rock" Johnson is obese. Conversely, someone with a small frame may have high body fat but a normal BMI.
Today we have a tendency to stigmatize obesity. The overweight are sometimes pictured in the media with their faces covered. Stereotypes associated with obesity include laziness, lack of will power, and lower prospects for success. Teachers, employers, and health professionals have been shown to harbor biases against the obese. Even very young children tend to look down on the overweight, and teasing about body build has long been a problem in schools.
Negative attitudes toward obesity, grounded in health concerns, have stimulated a number of anti-obesity policies. My own hospital system has banned sugary drinks from its facilities, making it impossible to purchase a non-diet soft drink there. Many employers have instituted weight loss and fitness initiatives. Michelle Obama has launched a high-visibility campaign against childhood obesity, even telling Dr. Oz that it represents our greatest national security threat.
The track record of governmental anti-obesity initiatives is mixed at best. One of the most widely reported was Denmark's so-called "fat tax," which consisted of a surcharge on all foods with a saturated fat content greater than 2.3 percent. The result? Danes switched to lower-cost versions of the same foods and began doing more of their shopping internationally, making their purchases in fat-tax-free countries. The fat tax lasted about a year before it was repealed.
In many cultures throughout history and even today, plump has been preferred to thin. Consider, for example, Shakespeare's Falstaff or the paintings of Peter Paul Rubens. In a community full of people who struggle to get enough to eat, being well-fed and having a well-fed family is often a sign of success. A hearty appetite generally indicates health and may even suggest that a person knows how to enjoy life.
This reminds me of a story about Herman Wells, the long-time president and chancellor of Indiana University. Wells was obese from childhood throughout his adult life. In preparation for minor surgery, his physician once advised him to lose 20 pounds. "That's easy," Wells replied. "I have done that dozens of times." Wells accepted his weight. He did not torture himself about it. In fact, he could even laugh about it, and he did so throughout all 97 years of his full life.
Is obesity bad for people? For some, especially patients who are extremely overweight, the answer is almost certainly yes. Would many overweight people benefit from exercising more and eating less? Again, the answer is likely yes. But this does not make obesity a disease. Many people are not harmed by carrying extra pounds, some may actually benefit from it, and we have yet to define it authoritatively. For these reasons, we should think twice before labeling obese people diseased.