But Berg and others acknowledge that it won't be easy to change the norm of a society in which it seems every advertisement features a gaunt model, in which dieting is an estimated $40-billion business, in which research dollars flow to scientists performing dieting research and in which Americans hold tight to the belief that anything is possible--even altering a body that may be genetically determined to be large.
To embrace a new model, Tribole says, "People have to grieve that they are never going to have a skinny body."
But Americans won't buy that concept, says Linda Webb Carilli, general manager of corporate affairs for Weight Watchers International. Five years ago, when Weight Watchers suggested that clients aim for a "healthy weight" as opposed to an "ideal weight," the idea flopped.
"To tell someone who is a binger, 'Don't think about your weight,' is not helpful," Webb Carilli says. "You can tell them to think about how healthy they are in other ways. But if that doesn't match their value system, if that isn't significant for them, it won't work."
According to a 1994 report in the Journal of the American Medical Assn., one-third of U.S. adults are overweight, a 25% increase from the 1960s. A quarter of all teenagers and children are overweight. Obesity rates have soared despite the proliferation of diet programs, pills and foods.
"The myth is that overweight is cured by dieting," said Connecticut psychologist Lisa G. Berzins before a congressional briefing on eating disorders in July. "The truth is that treating overweight by dieting most commonly results in eventual weight gain. Weight is a complex result of heredity, culture and lifestyle. It is not 'cured' by a pill or powder. Some large-size people maintain a healthful lifestyle, yet remain at above-average weight."
It's hard to pinpoint why so many Americans are obese when more people than ever are dieting and obsessing about their weight. Berg, a nutritionist who has studied the issue, blames obesity rates on fewer people smoking, more sedentary lifestyles, higher-fat diets and women being encouraged to gain more weight during pregnancy to have bigger babies (a tactic that may leave some with a healthy baby but a long-term weight problem).
Berg also blames Americans' approach to food.
"There is a big group of adults and kids who fit the criteria of dysfunctional eating: skipping meals, fasting, bingeing, chaotic eating, under- or overeating for reasons not to do with hunger but with body shape or feelings. They feel ashamed and uncomfortable," she says.
According to Berg, Americans' misguided notions about weight and food have led to a range of problems, including obesity, eating disorders, eating dysfunction (a less severe pattern of eating disorders) and size prejudice.
"We need to deal with these things in an interrelated way. Instead, we look at them separately. If we address obesity and help overweight kids, we may increase the other three problems' severity," she says.
For example, if children receive the message that being overweight is bad, then they may assume that it's OK to discriminate against fat people. Another example is the teenage girl who, disgusted with being plump, forces herself to vomit after eating.
"I work with people who have eating disorders, and I can see how . . . classic dieting, even in a healthful way, isn't really healthful," Tribole says. "If you are truly focusing on health and healthy behavior, you really can't do harm."
But many people assume that good health can be obtained only by achieving an optimal weight.
"One trouble that people have is they say, 'I'm exercising, I'm fit, my blood pressure and cholesterol are good, but I'm not the weight I want to be.' The problem with that approach is that it's a vanity issue. This can't be a vanity issue," Tribole says.
And, much worse than being somewhat overweight, the new-model proponents say, is weight cycling--losing, then regaining weight, which takes its toll on the body, particularly the heart.
"Disproportionate attention is paid to the risk of obesity while little attention is paid to the risks of weight fluctuation. And yet there is very good information on this; at least 10 studies have looked at this," Cogan says.
Lindsey Elan started battling her weight in high school. It was the beginning of an odyssey that would end with a diagnosis of an eating disorder.
"My girlfriend and I would eat these regimented diets, such as an apple for breakfast, salad with nothing on it for lunch and vegetables for dinner. We would do that for a week before the prom. In college, I would go on liquid diets," says Elan, 27, a graduate student who lives in Santa Monica.
After graduating from college and living alone for the first time, Elan began to binge and purge. She was eventually treated for bulimia.