Virus theory
More and more people around the world are obese and the statistics only tend to rise. As the market is flooded with diets, quick weight-loss tips, information about how, when to eat and also how to exercise, a study was published (January 2006) in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology by scientists of the University of Wisconsin, Madison which stated that Obesity is Contagious.
A lead researcher of the study, Leah D. Whigham said that there was growing evidence that certain viruses may cause obesity, making it contagious. The scientist found two human adenoviruses Ad-36 and Ad-5 which caused obesity in chickens and other animals, fact that lead them to believing that they could cause the same thing to humans. Another adenovirus Ad-37 is also suspected for causing obesity but further research must be done. Chickens inoculated with Ad-37 had much more visceral fat and body fat compared with the chickens infected with other adenoviruses, even though they didn’t eat any more. The Ad-37 group was also generally heavier, but the difference wasn’t great enough to be significant by scientific standards
Researchers now want to precisely identify the viruses that can cause obesity, then develop a test to see who actually is infected and conceive a vaccine.
Although I’m not a scientist, I personally don’t put much faith in this study. I also believe that is very dangerous to pass around a study like this before you have hard evidence. It would be very easy for a great number of obese or overweight people to just think that their weight problem is nothing that they can control and consider themselves ill. I can’t really imagine myself not shacking hands with overweight people being afraid not to catch obesity.
Social theory
A recent study (July 2007) published in The New England Journal of Medicine states the same thing, that obesity is contagious, but from radically different reasons than the previous study. The new data show that obesity is “socially contagious”.
In a huge social study spread over 32 years, researchers Nicholas Christakis and James Fowler, evaluated a densely interconnected social network of 12,067 people starting from 1971 to 2003, re-examining their weight over the years and determining whether weight gain in one person was associated with weight gain in his or her friends, siblings, spouse, and neighbors.
The study found that an individual’s chances of becoming obese increased by 57 percent if a friend grew obese. Within the closest friendships, the increased risk was 171 percent. Strange enough, obesity seemed to spread even if friends were geographically distant. “We were stunned to find that friends who are hundreds of miles away have just as much impact on a person’s weight as those who are geographically close” said one of the study’s authors. This led researchers to suggest that the effect wasn’t only due to sharing behaviors, such as eating together, but to sharing ideas about what constitutes an appropriate weight.

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Among friends and siblings, obesity seemed to spread only between those of the same gender. It was strongest between male friends - if one became obese, the risk for the other doubled - and between sisters. In a counterintuitive finding, the spread was less among heterosexual married couples and that’s because, as one of the authors said, people tend to look to others of their own gender when deciding what weight is appropriate.
The study also offered some hope for the ones that really try to lose weight: having a friend or relative who lost weight, makes their chances to do the same thing significantly increase.
I find this study very interesting and if it’s true it might just be a ground-breaking discovery in Health. I am also an overweight person and I’ve been obese (just a little bit) and if I think to all my friends I find that strange enough over 90 percent of them are slim, so the study isn’t accurate as I am concerned but overall it’s conclusions seem very plausible. So, if your weight is normal try to help your overweight friends by staying more around them and if you’re overweight don’t sever from friends like you but try to introduce them to some of your normal-weight ones.
Conclusions
It’s up to you to decide which study to believe, if any. Only the idea that obesity could be contagious, I believe, speaks for how much excess pounds have entered our lives. Higher and higher numbers of overweight population around the globe makes weight one of the most important health issues worldwide.
I wish you all to lose the extra weight and get healthy!
Listen here to Richard Atkinson as he speaks about viruses making obesity contagious.
Official site for The New England Journal of Medicine.