Is Weight Gain Contagious? Here’s Why You’re Vulnerable

When I was asked if weight gain is contagious, my first thought was, “Oh, that’s silly!” But it turns out that you can actually catch obesity. That’s according to a study from the University of California that says weight gain is contagious.

Behaviors can spread like pathogens

While we can’t catch obesity like we may contract the flu or a sexually transmitted disease, we can “catch” weight gain from the people around us. Together with the think tank Rand Corp., researchers at the University of California postulated that weight gain could be spread through a social contagion, or rather through our shared behaviors and beliefs.

Much like a yawning coworker can set off a chain reaction of yawns across the office, the behaviors and beliefs of an obese friend can create a domino effect that impacts how their friends feel about their own weight. However, unlike a disease, the amount of exposure to such beliefs takes on a different quality. As the authors state, in pathogenic situations, the more contact with a germ, the more likely a person is to contract the illness.

In a social contagion situation, people who have larger circles of friends on social media are less likely to notice individual pieces of information. The impact of an individual message is diluted when a person is connected with more people. “[H]ighly connected users are less likely to notice a particular piece of information, and they require stronger social signals to act, on average, than poorly connected users,” write the authors of the study.

Regardless of the subject, if you follow a small number of friends and accounts on social media that tend to deliver the same information, that could be a problem.

Social contagion trends

We see a similar echo chamber effect in politics, religion, and other closely-held beliefs. It’s why the body-positivity movement only included people who love their overweight bodies for a while. People followed one another and created a closed circle of information and influence that reinforced certain beliefs. Thankfully, the attitude about body positivity is changing to be more inclusive.

A study published in 2016 by a team of social scientists found quantitative evidence that social media is the perfect outlet to spread polarized messages while ignoring information that doesn’t confirm a person’s preferred beliefs. In this study, the team focused on how Facebook users interacted with two ideas that centered on conspiracy theories and science.

They found that people who belonged to different communities didn’t tend to interact with one another. So, the group more likely to believe conspiracy theories interacted with other conspiracy theorists who reinforced their views. And the science-minded users tended to stick to other science-minded people and groups.

It makes sense: Who doesn’t want to be right? When we surround ourselves with people who reinforce our preferred beliefs, we tend to disregard other points of view. The problem is, when false or harmful information is introduced into any social group, it can pollute the group as members spread it among themselves.

Your social network dictates your health

The same is true with obesity. The first study into obesity as a social contagion was a 32-year longitudinal study published in the New England Journal of Medicine in 2007. It examined an interconnected social network of 12,067 people from 1971 to 2003. Since it was part of the Framingham Heart Study, participants’ body mass index (BMI) information was available to researchers.

The findings were stunning. Obesity spread in clusters extending to three degrees of separation from the initial obese person. The research team also determined that a person is 57 percent more likely to become obese if they have a friend who became obese as well. In sibling situations, if one adult sibling gained weight, the other sibling had a 40-percent increased chance of weight gain. The same can be said for spouses: one spouse becoming obese increased the other person’s likelihood of obesity by 37 percent.

Why you’re vulnerable online and in person

It’s often said that we are a product of our environment, and it seems we now have scientific evidence of what we’ve known all along – our friends and family influence our health. For decades, personal trainers have used this fact to their clients’ benefit. In fact, the most successful weight loss or fitness plans involve the support of other people. Even just one gym buddy can help motivate you to workout more and put your health first.

Take a look at your social circle. If you don’t have friends from varying backgrounds, you are at risk of getting caught in an echo chamber. Then, examine the accounts you follow on social media. People and celebrities who promote body positivity are a wonderful addition to your other accounts. Follow people and organizations that make you feel good, but be sure to get several different viewpoints in the mix. For instance, a vegan chef, an obese yoga teacher, a bodybuilding celebrity, and a mom blogger make for a good mix of points of view. Scale that to a larger group, so you aren’t flooded with just one message about your weight or health. And if you want to lose weight, follow accounts that promote healthy, slow weight loss.

It goes beyond your social media accounts, though. As another study author, Ashlesha Datar told The New York Times, “Subconsciously, you are affected by what people around you are doing. When I travel to the Bay Area, for example, everyone is riding bicycles. You get there, and it seems like you have to buy a bicycle. If you move to a community where a sedentary lifestyle is the norm, you might join that.” Her 2018 study focused on military service member communities and obesity. As you might guess, she found that people in a face-to-face social network also succumbed to obesity as a social contagion.

If you want to be healthier and prevent obesity, consider your social life, both in person and virtually.

How are the people around you improving or hindering your health?

— Megan Winkler

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