Rising sea levels. Flying cars. Speculation about what the world will look like a quarter century from now are in no short supply.
But if new research released this week is correct, we can at least be sure of one thing: The forecast calls for fatness.
The study, released this week in the journal Obesity, suggests that by the year 2030, nearly every American will be overweight or obese.
Currently, figures from the U.S. Centers for Disease Control and Prevention put the prevalence of overweight and obesity in adults at about 66 percent. But lead study author Dr. Youfa Wang of the Johns Hopkins Bloomberg School of Public Health in Baltimore says that if current overweight and obesity trends continue, 86 percent of Americans could be overweight or obese by the year 2030.
Even more troubling, the authors note, "By 2048, all American adults would become overweight or obese."
"The results of the study show clearly how the future situation might become if current trends continue," Wang says.
Wang says that the increase in metabolic disease and other weight-related conditions could have a catastrophic toll on public health -- and on the public pocket. If these predictions come to bear, Wang and his colleagues estimate that the additional overweight and obesity burden could add up to an extra $860 billion to $956 billion per year in health expenditures to treat these conditions. All told, this would mean that $1 in every $6 spent on health care would be spent as a result of the overweight and obesity.
While some obesity experts are skeptical of the prediction that nearly all Americans will one day be obese, all agree that the problem is a growing one.
"It will never come to pass that all Americans are overweight, not even in 2048," says Keith-Thomas Ayoob, associate professor and pediatrics nutritionist at the Albert Einstein College of Medicine in Bronx, N.Y. "That may be a statistical possibility, but not a real one.
"However, the other prediction of 86 percent by 2030 could very well happen. We're almost there."
"I think they overestimate the eventual percentage and do not take into consideration the likely asymptotic nature of the curve," notes Dr. James Anderson, emeritus professor of medicine and clinical nutrition at the University of Kentucky in Lexington. But, he adds, "I think the rates of overweight and obesity are still increasing at a disastrous rate."
And other experts say that an almost completely overweight population, however frightening, could indeed be in store for the decades to come.
"Given that people in the U.S. continue to eat more and move less, I am not surprised at these findings," says Madelyn Fernstrom, founding director of the University of Pittsburgh Medical Center Weight Management Center.
Dr. Jana Klauer, a New York City-based physician and author of "How the Rich Get Thin," agrees.
"As a nation we have become too fat," she says. "The reasons are complex but can easily be summarized by: too much food and too little exercise. Highly palatable, cheap foods are abundant. ... The focus on exercise is absent in most Americans' lives. Yes, I think the predictions will come to pass."
Signs of a Turnaround?
However, not all obesity-related news in the past year has been quite so bleak. In November 2007, a CDC study found that there was virtually no change in obesity rates among men and women between the periods of 2003-04 and 2005-06.
"Perhaps the authors of this paper did not consider the newer data," notes Mary Beth Kavanagh, instructor in the department of nutrition at Case Western Reserve University in Cleveland. "This is not to say that the problem is not significant and carries a tremendous cost to society and a burden on the health care system. [But] I do not honestly believe that we will hit the 86 percent mark for overweight and obesity."
However, Wang says this new data is eclipsed by that used in his study, which takes into account three decades of research.
Additionally, some suggest that even though recent reports indicate that childhood obesity, too, may be leveling off somewhat, the problem is far from solved.
"Kids may be getting overweight more slowly, but in certain groups the news isn't good," Ayoob says. "Mexican-American and African-American kids fare the worst, and the children in the upper percentiles seem to be gaining faster than the rest of the child population.
"Also, we have to remember that we'll be sending more of our children into adulthood with obesity, so more of them will already be at a disadvantage."
Path to a Different Fate
Obesity experts agree that certain measures, taken now, can head off major problems in the future. Whether or not the country will follow through, however, is a matter of debate.
"We are terribly, ominously off-course," says Dr. David Katz, co-founder of the Yale University Prevention Research Center. "To close the gap, we need to fix everything that's broken -- from neighborhoods without sidewalks, to the high price of produce, to food marketing to children, to misleading health claims on food packages, to school days devoid of physical activity and school cafeterias devoid of healthful offerings. The list goes on and on."
Others cite individual responsibility for diet and lifestyle habits. Dr. Neal Barnard, founder and president of the Physicians Committee for Responsible Medicine (PCRM) and a staunch supporter of a vegetarian diet, says dietary modification could be a crucial step in solving the problem.
"U.S. eating habits are nowhere near where they should be," he says. "The average American eats 50 pounds more meat and 20 pounds more cheese per year, compared to the 1960s. ... I would strongly encourage Americans to adopt more vegetarian meals.
Fernstrom, on the other hand, says drastic approaches to weight control turn most people away.
"We talk and don't do. People are walking encyclopedias of information, but making small changes over time is key," she says. "In the U.S., our 'all or nothing' approach to weight management won't work. Slow and steady wins the race."
But no matter the means, most agree that the research could serve as a needed alarm to help jump-start solutions to the nation's growing weight problem.
"Predictions should always be viewed as possibilities, not guarantees, but the information presented in this study should cause all Americans to focus on how they can change behaviors to promote health, their health," says Connie Diekman, director of university nutrition at Washington University in St. Louis and former president of the American Dietetic Association.
"If the projected numbers do or do not come to be, this study is a good wake-up to the fact that Americans aren't taking control of their own health."