Americans spend billions of dollars every year to prevent obesity and billions more to lose pounds once they're overweight.
Yet, Americans keep getting heavier.
Leon Colucci, like many other dieters, knows the frustration.
Weight Watchers? He tried it.
The Atkins low-carb craze? He went for that, too.
All his diets have worked at first, but the weight eventually returned. Now, he seems stuck at an unhealthy 300 pounds.
"I don't gain weight lately, but I can't lose it, either," said Colucci, a veterans affairs specialist for Erie County's Office of Public Advocacy.
His experience represents some hard-to-swallow truths about how to address the growing numbers of overweight and obese adults and children in the nation.
Despite all the advertised claims, studies show that diets by themselves generally produce only modest weight loss in the long run.
And, as hard as it is to take pounds off, the science of dieting has found that it is even harder to keep from regaining weight, especially when cheeseburgers and chicken wings are cheap and plentiful.
If diets alone aren't enough, what does work best, short of surgery?
The answer isn't so clear.
But it is becoming an increasingly vexing question as the health and financial costs of obesity rise, a point underscored by the recent news that BlueCross BlueShield of Western New York would fund a major study in Buffalo to look for a better way.
"The more we look into this, the more we see that obesity is an illness tied into the world we live in. We have a biology that discourages us from losing weight in a society with relentless pressure to overconsume. It's a losing battle," said Dr. Howard Eisenson, director of the Duke University Diet and Fitness Center.
>Demand for surgery
Today, an estimated 65 percent of U.S. adults 20 and older -- more than 97 million people -- are considered overweight or obese, according to the Centers for Disease Control and Prevention.
Health experts now view obesity as an epidemic and worry about increases in disorders related to excess weight, including diabetes, stroke and heart disease.
The obsession with fat has led to skyrocketing demand for surgical treatments, including gastric bypass procedures. About 170,000 operations were done in the United States in 2005 at a cost of about $4.5 billion.
The procedure, known as bariatric surgery, has been shown to be helpful for the severely obese, and more effective than diet and exercise alone. But while many patients meet the criteria for surgery, the procedures are risky, expensive at around $26,000 a case and not always an attractive or available option.
"We need to get to people further upstream before surgery is considered. If we can keep people healthier, we can lower medical costs," said Philip Smeltzer, vice president of health improvement at BlueCross BlueShield.
The health insurer spent $4.5 million on bariatric surgery last year in the Buffalo area and expects that figure to increase.
No one wants to hear it, but there is no easy path to losing weight.
Recent evidence suggests that dieters in aggressive programs will lose only an average of 10 percent of their starting weight in the first six months and then run into problems that often lead them to gain weight back.
That seems slight, although studies indicate that losing 5 percent to 10 percent of body weight can bring health benefits.
With so many diets clamoring for attention in books, magazines and television, it's remarkable that little is known about how well they work.
>Cheating is a problem
Last year, University of Pennsylvania researchers looked for published evidence on the effectiveness of 10 popular diet programs, including Weight Watchers, Optifast and Jenny Craig.
The best evidence they could find was for Weight Watchers. And the results: participants lost 5 percent of their weight in six months, or about 10 pounds. After two years, the average weight loss was about three pounds.
The diets aren't really the problem. It's sticking to them for the long haul that is.
Colucci probably speaks for just about anyone who ever counted calories when he confesses he is prone to cheat on his diets and doesn't exercise enough.
"It's frustrating," he said. "I'm self-conscious about my weight, but I also have to admit that I have not tried hard enough."
A consensus is growing that successful weight loss requires one strategy for losing pounds and another one for preventing the pounds from coming back.
"We are still focused on weight loss. We know diet and exercise can work. What's missing, is an effective way to maintain weight loss, which is much harder to do," said Dr. James Hill, director of the University of Colorado's Center for Human Nutrition.
Scientists are starting to put together a picture of what accounts for the rise in obesity and why fat is such a challenging foe.
For instance, experts believe a chemical "hunger" hormone works to keep the body from starving by insistently telling the brain to eat when we lose weight.
One other theory suggests that people developed a gene that allowed them to store fat during times of plenty so that they did not starve during times of famine.
"We're built to survive times of hardship, when we would not know when we would find our next meal. We don't live in that world anymore," Eisenson said.
Still, some dieters do lose weight. They are able to avoid the supersized portions, turn off the television and get some exercise.
Why do they succeed when others don't?
Researchers are finding answers from the National Weight Control Registry, which has been tracking more than 5,000 people who have kept at least a 30 pound weight loss for one year or longer.
>Motivation is the key
Again, there are no magic bullets: eat a steady diet, including breakfast; do regular physical exercise that builds gradually in difficulty, such as walking; set realistic expectations about success; avoid relapses, which are very difficult to overcome; and persevere.
"The big barrier is maintaining a level of motivation," said Hill, a co-founder of the registry. "That's why we favor a small changes approach. You may not lose as much weight this way, but it's more likely to be permanent."
Experts like Hill, Eisenson and others see several hopeful strategies against obesity: improving efforts at prevention and finding more effective treatments by combining multiple therapies over longer periods of time.
As health costs rise, health insurers want more answers about what works best, too.
In Buffalo, the Blues are funding a five-year, $5 million study at the University at Buffalo that will examine four different weight-loss regimens, comparing their cost and effectiveness to surgery.
They include low-calorie and very low-calorie diets, with medication and behavioral therapies that incorporate exercise, education and motivational strategies.
"Behavior modification is probably the key to success -- get people not to resume old habits," said Dr. Michael Noe, the principal investigator.