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The Obesity Crisis: Americans' bodies are out of balance

Posted - Sep. 8, 2004 at 12:20 p.m.



This archived news story is available only for your personal, non-commercial use. Information in the story may be outdated or superseded by additional information. Reading or replaying the story in its archived form does not constitute a republication of the story.

EDITOR'S NOTE: This is the first in an occasional series on the nation's obesity crisis and how people in the Northwest are affected. Tomorrow, a look at the links between poverty and obesity.

At 7, Laura Walter attended her first Weight Watchers meeting.

The next year, she experienced a dieting epiphany on a suburban Colorado playground.

"You are a toothpick," a fellow third-grader observed, her finger poking into the bones of little Laura's chest.

"I felt really good for the entire day," said Walter, now 35.

Her 8-pound weight loss, however, came courtesy not of a carefully monitored eating plan, but after a nasty kidney infection that landed Walter's pudgy body in bed at home for a week.

"Then ... I thought, the only way I'm ever going to get thin is to be sick."

Nearly three decades later, with a body mass index in the low 50s (obesity is defined as a BMI of 30 or greater), Walter is still plagued by guilt when she eats a sugary treat.

"We're all sort of taught if everyone eats perfectly, we'll have this nation of nice-looking, aesthetically appropriate people," said Walter, who works in marketing at a Seattle investment firm.

Scientists are just beginning to understand the biological mechanisms that lead to a lifetime of containing urges and waistlines for people such as Walter.

But willpower is perhaps the least instructive explanation for the growing number of overweight Americans, say many obesity experts. Most now believe obesity is a disease triggered by a food-rich, activity-scarce environment in people who are genetically susceptible to weight gain.

And the government appears to agree, with Medicare opening the door for coverage of obesity treatments earlier this year and the Internal Revenue Service now allowing tax breaks for some weight-loss programs.

Runaway fat

Roughly two-thirds of American adults are overweight or obese, with excess weight threatening to overtake tobacco as the No. 1 cause of preventable deaths in the United States, according to a study published in the March 10 issue of the Journal of the American Medical Association by researchers from the federal Centers for Disease Control and Prevention.

About 16 percent of children between 6 and 19 are carrying around too many pounds, according to the National Institutes of Health.

And some groups, including African Americans, Latinos and the poor, are more likely to be overweight.

Skyrocketing obesity rates are linked to an explosion in diabetes cases among children and adults. Too much fat also increases the risk of an ever-growing list of health problems, including heart disease and many different types of cancer.

An estimated 400,000 people will die this year from obesity-related illnesses, according to the CDC.

Seattle, with its outdoorsy, active ethos, is not immune.

In this land of hikers and bikers, skiers and sailors, more than half the residents of King County are overweight and 16 percent, more than double the number 15 years ago, are obese, according to Public Health -- Seattle & King County.

Adults in King County weigh an average of 12 pounds more than in 1987.

Why the added bulk?

Experts say the answer is all around us -- in the cars we insist on using for every outing, in the giant mugs we fill with whipped-cream topped mochas, in a culture where everybody seems to be always rushing around and yet sitting still most of the time.

Close to three-quarters of county residents are either completely sedentary or don't get enough exercise to meet the CDC's minimum guidelines for physical activity -- 30 minutes of moderate activity five days a week.

"The level to which you can be physically inactive in a day is utterly amazing," said Dr. Brent Wisse, who treats overweight and obese patients at Harborview Medical Center's Weight Disorders Clinic. "You're not going to fix that by going to the gym and spending half an hour on the treadmill."

What controls the desire?

The decision to snack on a candy bar rather than carrots and the choice to watch television instead of going for an evening jog ultimately lies with individuals.

So, isn't the key to controlling the epidemic and maintaining a healthy weight all about willpower?

Scientists who study body weight say no.

They are more convinced than ever that sluggish metabolisms and out-of-control hormones, rather than gluttony and sloth, drive the proclivity to gain weight and keep it on.

"The biological control of body weight tends to be more powerful than the willpower a person has," said Dr. Michael Schwartz, an obesity researcher at the University of Washington.

Only a small percentage of obese people are fat solely because of a metabolic syndrome linked to a single gene, Schwartz said.

But pair a genetic susceptibility to weight gain with an environment in which little physical effort is required to get to an abundance of cheap food and you've got a recipe for rising obesity rates.

"We've got an organism which has evolved to store fat in an environment which is just making it way too easy to do that," said Dr. Rudolph Leibel, a molecular geneticist at Columbia University who studies obesity, during a January talk sponsored by the National Institutes of Health.

Weight gain results from an incontrovertible equation: taking in more calories than you burn off.

Beyond the basic physics, experts say there's an extremely nuanced system that regulates how much food and physical activity the brain demands -- much of which scientists are still figuring out.

Researchers believe there are several hundred genes responsible for the body's weight regulation system. They control a variety of unconscious drives, including how much you fidget, when you feel full and a taste for fatty, sweet foods, say researchers.

"People come to the conclusion that if you're obese it must be because you've chosen to lift the fork too often and not to move around," Leibel said. "The question is what are the mechanisms that are controlling the desire or need to eat and expend physical activity?"

Most of the breakthroughs in obesity research in the past decade can be traced to the hypothalamus, a fingertip-sized portion of the brain that helps keep the body in metabolic balance, secreting hormones that regulate hunger, blood pressure, body temperature and thirst.

The first experiments linking the hypothalamus to body weight were performed on rats in the early 1940s. Researchers noted that the rats got fat when a portion of their hypothalamus was removed or damaged.

Experts believe many obese people suffer from resistance to leptin, a hormone produced in proportion to fat cells that tells the hypothalamus how much stored energy the body has to call upon.

In 1994, Dr. Jeffrey Friedman, a scientist at Rockefeller University in New York, discovered the gene for leptin. He named it after the Greek word leptos, which means thin. Friedman found that mice bred without the gene for leptin gained inordinate amounts of weight.

Scientists compare leptin resistance to Type 2 diabetes, in which the body stops recognizing insulin. In both cases, it's unclear why or how the resistance develops, Leibel said.

With their sensitivity to leptin dulled, people with too much body fat don't receive the signal to stop eating.

A vicious cycle ensues.

More leptin is required to quell hunger, but the only way to turn up the level of leptin is more fat.

"You end up reregulating your body at an elevated leptin level," Schwartz said.

A constant battle

Walter and her fiance, Hasan Edain, moved to Seattle two years ago from California after losing their jobs in the high-tech bust.

They're planning a July 4 wedding on Lake Union.

"I love fireworks," said Walter. "I like the idea of having them at my wedding and on every anniversary."

Edain, 35, is also obese. He takes medications for high blood pressure and has been warned to watch his blood sugar.

At 5 feet, 2 inches tall and close to 300 pounds, Walter doesn't have diabetes, heart disease or any of the other maladies associated with obesity. She knows that could change with age, but for now her most pressing concerns are emotional.

Getting on a plane messes with her mind. The other passengers, she thinks as she makes her way to her seat, dread sitting next to her.

Shopping for a wedding dress is another concern. In a size 22, her style options are limited.

Walter's family always tried to encourage her to control her weight. Her mother cleared the kitchen of fattening snacks and helped her daughter keep a food log.

Her brother, naturally wiry and athletic, never had weight problems even though he and Walter both took every opportunity to sneak foods that weren't allowed in their cupboards. "He ate a ton of sugar just like me; it just didn't happen to show up on his frame."

Treating obesity

Shedding pounds appears to trigger powerful survival mechanisms in the body that evolved to preserve energy and restore weight to a previously higher level -- a dirty evolutionary trick given our calorie-rich environment, experts say.

That's why eating less and exercising more -- the most basic weight-loss strategy -- will probably never be enough for some people to reach a healthy weight. "People tend to say, 'Well, you did all right for awhile but it's clear you don't have the willpower and that's how you got fat in the first place,' " said Leibel, the Columbia University expert. "It turns out that's not what happens. Instead, the body responds by slowing the metabolism down, making you hungrier and doing a number of things to hormones that cause them to gain back the weight."

Overweight people who try to cut back on calories feel chronically hungry and cold, and women often have trouble with their menstrual cycles, Leibel said.

Current weight-loss drugs yield minimal results and come with a host of unpleasant side effects, including diarrhea. And while stomach surgeries that restrict food intake are more effective, they can lead to serious complications and death.

Genes are about 70 percent responsible for body weight, determining a set point that Dr. David Cummings refers to as the "body weight ballpark."

"Within that body weight ballpark, you have the ability to slide up or down by 5 or 10 percent by dint of will and dietary efforts," said Cummings, an obesity researcher from the Veterans Affairs Puget Sound Healthcare System and the University of Washington. There are sensational examples of dieters who've lost 150 pounds -- and kept it off -- through diet and exercise alone, but those cases win the spotlight because they're so rare, Cummings said.

"For most of us that (5 to 10 percent ) is about all that is reasonably achievable," he said.

Theoretically, injecting dieters who've lost weight with leptin could trick the brain into thinking the body fat is still there, quieting hunger pangs and speeding up the metabolism.

But so far, leptin has not been successful as a weight-loss tool, probably because obese people have developed a resistance to the hormone, said Schwartz.

UW researchers also are studying ghrelin, a hormone produced in the stomach that sends hunger signals to the brain. Studies indicate that ghrelin levels are drastically reduced in patients who've had gastric bypass surgery.

By contrast, ghrelin levels increased in dieters who tried to lose weight by eating less.

That could explain why surgery leads to more dramatic weight loss than diet and exercise, said Cummings, who first linked ghrelin to the urge to eat at meal times.

But there's still a lot that scientists don't understand about excessive weight gain.

Only a handful of the genes involved in regulating body weight have been identified and it's unclear how they interact. Researchers also don't know how changes in hormone levels affect long-term weight control.

More effective drug therapies are on the horizon, but remain years away, said Dr. Barbara Kahn, chief of the division of endocrinology, diabetes and metabolism at Beth Israel Deaconess Medical Center in Boston. Kahn studies leptin and other enzymes that control hunger and activity.

"We don't know where to intervene," Leibel said. "We don't know the best targets for the drugs."

A disease?

Schwartz takes a slightly different approach than many obesity researchers.

He believes the human body is not necessarily more inclined to store fat.

People who gain weight, therefore, suffer from a malfunction in their weight-regulation system.

If that's true, it makes an even stronger case for obesity as a disease, rather than an expected reaction to a food-rich, activity-deficient environment, says Schwartz.

"If there was no protection against weight gain to begin with, why would you have such differences in the rates of obesity when people are put in the same environment?" Schwartz asked.

Only about one-third of the population has a genetic makeup that appears to shield them from piling on pounds, Schwartz said. The rest suffer from varying degrees of susceptibility to overweight and obesity sparked by certain environments, he says.

Still, many aren't sold on the notion that obesity qualifies as a disease.

Tom Cecil, whose 5-foot-9-inch, 215-pound frame is obese by federal standards, traces the rising tide of corpulence to a much simpler root.

"It's a matter of how much food we stuff down our own necks," said Cecil, a 65-year-old Metro bus driver who lives in Lake Stevens.

"When I'm the sole cause of the condition, how much of a disease is that? It's just that my willpower isn't strong enough to overcome that urge to eat more."

In the continuing struggle to make peace with her body, even Walter says she has a hard time letting herself off the hook for her size.

"I have this very heightened awareness when I'm eating of, 'Look at me, I'm making the bad choices,' " Walter said.

Despite the body's unconscious weight-control system, experts say overweight and obese people should still strive to eat better and get more exercise. Even modest weight loss has been linked to big improvements in health.

"None of this should really be interpreted as saying people have no responsibility for their weight," Schwartz said.

Kahn, the Boston physician, agrees. "There's nothing to really gain by trying to convince someone they have a disease," said Kahn, adding that societal remedies, such as healthier school lunches and cities built to encourage walking, are also necessary to treat the obesity epidemic.

"It's very important to encourage people to still put effort into a healthy lifestyle."

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