Her most recent book, "Rethinking Thin: The Science of Weight Loss and the Myths and Realities of Dieting" (Farrar, Straus and Giroux, $24), suggests that when it comes to diet and exercise, we are basically predestined by genetics. It is the old "set point" argument: No matter how hard we try to change them, our bodies will eventually return to their predestined weight.

Kolata was in town recently for a lecture and book-signing, and to host the 2008 Franklin Institute Awards. I'm familiar with the svelte exercise enthusiast's 2003 book, "Ultimate Fitness: The Quest for Truth About Exercise and Health," an overview of the fitness industry and her personal quest for fitness, and was eager to hear her speak.

But my excitement faded as I listened.

According to Kolata, it's metabolism, not lifestyle or habits, that keeps the majority of Americans obese or overweight.

She takes personal responsibility and choice out of the equation and even questions if there "is such as thing as free will when it comes to eating and body weight."

In my opinion, Kolata ignores the obvious: our mostly sedentary lifestyle and gluttonous behavior that has us consuming an excess of 3,700 calories a day.

She began her lecture as she did her book, with a discussion of a two-year study conducted by the University of Pennsylvania comparing Atkins and low-calorie diets.

Atkins seemed to be the winner at first, with dieters losing an average of 4.4 percent of their body weight - about 9.5 pounds - while the low-calorie dieters lost about 2.5 percent, or about 5 pounds.

But by the end of the two-year study, most participants had regained most, if not all, of their weight.

About 64 percent of Americans are overweight or obese, and Kolata said it's nearly impossible for most of them to permanently lose weight. If a "healthy lifestyle" were enough, why would two-thirds of the nation have a weight problem?

"Everybody has tried that - give me a break," Kolata proclaimed. "How do you reset heredity, environment and brain craving calories?"

She pointed to a 1986 Denmark study that found adopted children had the same weight and height as their biological parents, regardless of the modeling their adoptive parents offered.

As far as Kolata is concerned, the battle of the bulge is "much ado about nothing," more of a "moral panic" than a genuine public health concern. For proof, she pointed out that people today are living longer - "50 is the new 30."

Interesting, but I'm still not buying it.

Sure, we're living longer, but what about the quality of life? You can be ill and still live a long time.

And how can Kolata deny the shocking rates of heart disease, stroke, diabetes and many cancers that are linked to obesity?

Perhaps some of the studies she cited were flawed.

For example, eating healthier foods does not mean one is not overeating. Eat too many fruits, nuts and grains and you'll gain weight.

And at what level were study participants exercising?

My guess is that many were doing their fitness routines at a mild to moderate rate - fine for general health but not enough to significantly change your appearance. For that, intense and consistent effort is required.

My admittedly unscientific observations have shown me that most people do not make heroic attempts when it comes to weight loss. Most people want easy and effortless weight loss.

Kolata's forlorn conclusions aside, your fate is not sealed. Biology is not destiny.

With fortitude, persistence and determination, people can achieve amazing things. When it comes to weight loss - or anything - I say, live by the words of the late Winston Churchill: "Never, never, never give up!" *

Kimberly Garrison is a certified personal trainer and owner of One on One Ultimate Fitness in Philadelphia (www.1on1ultimatefitness.com).

E-mail her at

kimberly@1on1ultimatefitness.com. Her column appears each Thursday in Yo! Chat with her on her Daily News weblog, the Girlfriends' Locker Room, at www.girlfriendslockerroom.com. Her new podcast, "Philly Fitness and Health," is available for download every Thursday at www.philly.com.