What is Oprah Winfrey's "normal" weight? This question springs to mind in the wake of the Centers for Disease Control and Prevention's announcement that only about 30 percent of the nation's adult population is currently at what the CDC defines as a normal weight (according to these definitions, 34 percent of Americans are "obese," and 33 percent are "overweight. Three percent of us are supposedly underweight).

Winfrey's three-decade-long battle with her body is a classic example of the weight cycling almost all chronic dieters undergo. Her weight has fluctuated between 150 pounds (she achieved this about 20 years ago by losing 67 pounds after eating no solid food for several months) and 237 pounds. Three years ago, during a thin cycle, she weighed 160; today she weighs 200.

Winfrey is between 5 feet 6 inches and 5 feet 7 inches tall, so it's worth noting that, even when she's in a thin period, she's almost always "overweight" according to the government's preposterous definitions. ("Normal" weight for her is supposedly below 155 pounds; she's currently "obese.")

Winfrey is, of course, both fabulously wealthy and a famously driven and hard-working person. If someone with her psychological and economic resources can't even achieve a normal weight, let alone maintain it, what hope is there for the other 145 million adult Americans who have failed to maintain a government-certified body mass?

In regard to that question, there's bad news and good news. The bad news is that it is quite literally impossible for the large majority of Americans to maintain the government's definition of a normal weight.

The good news - and this really can't be stated strongly enough - is that this definition is completely fraudulent. The notion that it's "normal" for adults to have a body mass index between 18.5 and 24.9 is a classic piece of social insanity. Indeed, it's every bit as bizarrely unscientific as declaring that a "normal" height is between 5 feet 6 inches and 5 feet 9 inches.

(Anyone interested in a detailed debunking of this destructive nonsense can consult any of a host of recent academic publications, including books such as Eric Oliver's Fat Politics, Sander Gilman's Fat, Michael Gard's and Jan Wright's The Obesity Epidemic, and my own The Obesity Myth.)

It's actually hard to get one's mind around how crazy it is to claim that it would be "normal" for Oprah Winfrey to weigh less than 155 pounds. In fact her entire adult life is a testimony to how utterly abnormal it is for her to weigh less than that.

Adding yet another layer of craziness to all this is the fact that, even at her very thinnest, Oprah has always been more or less "fat" according to the extraordinarily punitive standards employed by and against contemporary middle- and upper-class American women. (In such circles, a 150-pound woman of average height is certainly nowhere close to what is longingly defined as "thin.")

Fortunately, there are some signs that Winfrey herself might be willing to start using her fame to start fighting back against at least some aspects of all this insanity. Although it's discouraging to hear her talk about being "addicted" to food - this sounds like someone saying she's addicted to air - it's encouraging that she's also saying it's no longer her goal to be thin.

Instead, she says she wants to be "strong, healthy and fit."

Those are eminently realistic goals - for her and for tens of millions of other Americans who couldn't possibly achieve a "normal" weight if their lives depended on it.

And a key to achieving those goals is to reject the absurd and destructive idea that staying within a very narrow and completely arbitrary weight range - a range, by the way, that doesn't even correlate with the best health outcomes - is somehow "normal."

Paul Campos is a professor of law at the University of Colorado. He can be reached at paul.campos@colorado.edu.