Despite reports that the rate of obesity among adults in the United States may be slowing, the new forecast suggests Harvard and MIT to the contrary.

Instead, a sophisticated model takes into account obesity an infectious disease, the Group estimates that obesity in adults to rise another 40 years for the comparison. And before you reach this level, 42 percent of adults are obese, predicted the team.

Last year the U.S. Centers for Disease Control and Prevention, obesity in adulthood by 34 percent, another 34 percent of Americans are overweight but not obese.

“This is certainly true that the proportion of overweight people has slowed,” said study author Alison Hill, a student at the Harvard evolutionary dynamics program, biophysics program. “But our results show that this is not the end.”

The study appears this week in the journal PLoS Computational Biology.

It is expected the scenario un”best,”said Dr. David Hill edge, a researcher at Harvard University, who was also involved in research. This means that the rate of obesity could further increase by 42 percent.

Obesity than body mass index (BMI) of 30 or set higher. For example, a distance of 5 meters a person – has 5 inches, weighs 200 pounds and a BMI of 33 is considered obese.

Modeling was made after examining the prevalence of obesity through social networks of long-running Framingham Heart Study Network. Analysis, a social network with family, colleagues, friends and neighbors. Prevalence of obesity in adults in the United States in recent decades as a result of social contacts can not be ignored, and the border said Hill. This idea is the pollution sociale””teoria obesity.

According to this theory, normal-weight person has a 2 percent chance of obesity in a given year, according to researchers.

This increases the number of obesity 0.4 percent have social contacts with all that a man with five contacts overweight doubles the risk for obesity.

On the other hand, when it comes to weight, obese adults, a 4-percent chance of heavy losses enough to be in a given year, the team found.

But they found that weight loss was much to do with social contact. So fat man, time with friends and spends a normal weight, not necessarily in pounds as a result of these contacts to lose.

Other factors the spread of obesity, said Hill border, including the transfer speed di”non-social “by overweight, such as easier access to healthy foods,”the rate of recovery of loss or obese BMI, where people under 30.

In the transmission of parties other than the spread of obesity important social, Rand said the role of social transmission past four decades can be increased.

Just hang out with people that obesity increases the risk of obesity is unclear. Speculation, Rand said that over time, as we more and more by e-mail, Internet and social networking, social transmission factors, of course, played an important role. You could say that what “changed e”normale food if you work friends fat.

The results have implications for public health – suggests that policy makers can do to attack the obesity epidemic – but also a message to the individual, “said Hill.

“” A good place to take home really is interested to help your friends to lose weight, “said Hill.” The more friends you have fat, a better chance to win. ”

Another expert, James A. Fowler, Professor of Medical Genetics and Policy Studies at the University of California, San Diego, said the study, with its gloomy forecast oils 42 percent, there are some bright news.

“The good news is that we include obesity epidemic, and” model “the authors achieved an adequate framework for understanding how obesity back,” he said.

Fowler is a book about social relationships with Dr. Nicholas Christakis, the other co-author of the study of new models, Edge Hill.