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Nutrition Articles  ›  Pitfalls and Plateaus

Are Your Friends Making You Fat?

Weight Loss News Flash

-- By Liza Barnes, Health Educator
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If your friend who lives across the country comes down with a cold, you’re surely not going to catch it from her. But if she becomes overweight, that just might spread to you.

So say researchers from Harvard Medical School and the University of California, who published research in a July 2007 edition of the New England Journal of Medicine. After analyzing data from 12,067 individuals, they found that when one individual becomes obese, the chance that his or her friend will become obese increases by 57 percent—even if their friend lives far away, and especially if their friend is of the same sex—71 percent in that case. Other members of people's "social network" were also affected: their siblings’ risk increased by 40 percent and their spouses' by 37 percent. In contrast, a neighbor, if not a part of their social network, experienced no increase in risk.

Obviously, weight gain isn’t contagious in the same way a cold is contagious. Rather than being spread through the transmission of bodily fluids, like a virus, obesity is “socially" contagious—it can be spread through the transmission of behaviors and social norms. People within a social network often engage in health-impacting behaviors together, such as Friday night parties with too much wine and cheese or working lunches of fatty restaurant fare. These behaviors may result in weight gain, especially if they become habits. Even more importantly, each person within the social network serves as a standard by which others in the network may compare themselves. The 10-pound weight gain your best friend is wearing makes you feel a little less guilty about the extra five pounds you’re sporting, and if fast-food is an acceptable meal for your sister-in-law, you may develop a more lackadaisical attitude about dinner in your own house.

Action Sparked: Don’t trade in all of your overweight friends for trimmer models just yet. Rather than asking what your friends can do for you, do what you can for your friends. Examined from a different angle, this study shows that while unhealthy behaviors are contagious, so are healthy ones. Instead of waiting for your friends to get on the path to a healthy lifestyle, assume the role of the trailblazer in your group. Suggest hiking instead of a trip to the movies, and you’ll both benefit.

This is one of the basic principles on which SparkPeople was founded. One person, doing what they can to get healthy and fit, can be a powerful influence to many others—a spark that ignites a change. Here are some ideas to “Spread the Spark” so that your healthy habits are contagious to your friends and family:
  • Join a gym with a buddy. Many times, membership rates are lower (and the workouts are more fun) when you're with a friend. And just think of how many people the two of you have the power to influence!
  • Choose social activities that are active. If you’re into sports, organize or join a soccer team. Evening walks with a nearby friend, indoor rock climbing, bicycling, bowling and canoeing are other good bets.
  • Throw a fitness party to share the fun of exercise with your friends.
  • Get connected with a SparkTeam. Be a model of good health habits to other SparkPeople members, and sit back while they positively impact you. You can join an existing Team or start one of your own.
  • Here are even more ideas for you to Spread the Spark to others!
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About The Author

Liza Barnes Liza Barnes
Liza has two bachelor's degrees: one in health promotion and education and a second in nursing. A registered nurse and mother, regular exercise and cooking are top priorities for her. See all of Liza's articles.

Member Comments

  • LIZZIED_79
    I think that this study is insulting. While I have joined the Spark community to make healthy changes in my life, I understand that thin does not equal healthy. There is already a fear cultivating around our "obesity crisis" in America and this only contributes to the prejudice that heavy people face each day. You can not catch "fat" and although the article doesn't outright suggest it, it only contributes to this issue of fear and prejudice.

    However, I will admit that the company you keep also creates a positive or negative culture in your life.Yet, I don't see many articles on people who have friends who drink too much and so they may become alcoholics. I don't chose my friends by weight , but I will tell you those I have that are heavy are very active.
    - 11/18/2012 1:28:13 PM
  • KARLYN
    Just started a hiking group and it is growing...fast! So much fun to do as a get-together, great idea - 7/13/2012 4:27:46 PM
  • If this is true, then I hope my weight loss can affect their weight loss. - 5/9/2012 8:01:05 PM
  • i think its true to a certain extent. i do agree that environment affects what you do and the ppl in it. but then there are also your tendencies. I think thats why it may be good to not hang out too much with certain friends. they just zapp it out of you. but on the other hand if you do still hang out with friends who aren't coducive to ur new lifestyle, its good to get your support elsewhere, like sp. - 1/16/2012 3:34:25 PM
  • As with all articles, they are here to enlighten us in different topics that will inspire us to think and look at things differently. They are just guides and should be leaving us thinking how we can look at things in a way that will help us change the things we need to change. Society changes daily. You have to just know who you are and where you want to be, make a life plan for yourself and do your best to stick with it. Whether or not my friends are overweight or skinny, make no difference to me. And, yes I might divulge in eating that I wouldn't normally when around them, but that is MY choice. Knowone forced the spoon to my mouth and said eat it. It was my choice. This article is telling us to make good choices and not always follow the lead of friends and family. Keep yourself in check and do things in moderation. Wonderful article and I enjoyed the fact that it showed us a different way of looking at why we can end up obese. :) - 11/18/2011 8:14:14 AM
  • I honestly have never thought about that and that makes a good point. I'm going to try these tips I did not realize that all these things around me could be a contributing factor to my weight. Not saying that its the reason but the words "lifestyle change" are becoming so much clearer to me now WOW - 10/19/2011 12:45:05 AM
  • I find that my friends are pretty much the only reason I ever go out to eat or drink. I've made attempts to curve that group habit with more physical activities - but unfortunately, the majority of them don't WANT to do active stuff. My suggestions to do outdoor activities are inciting groans now. At least the at-home dinner parties have fewer calories (and cost less). I guess it's time to diversify the friend circle some more. - 9/7/2011 1:43:53 PM
  • The basic premise of the article is that we pick up habits from the folks with whom we associate. It's true! How many parents have worried about -- and talks to their kids about -- the "kind of friends" you choose? We're all human and we're influenced by others around us. It's great for me to focus on my own healthy lifestyle choices, and I love to be a good influence on others. But this article just points out that the unhealthy lifestyle choices can also be a negative influence. We see it in families, and in groups of associates. I have to say that when I'm healthy, moving, active . . . that people who can't (or choose not to) "keep up" tend to drop off/ That's their choice, too. - 8/2/2011 11:41:12 AM
  • When I smoked, I would never, ever light up around non-smokers, because it made me feel ashamed. Smoking was what I did with my smoking friends. And, I'm sorry to admit, we really did sabotage each other's efforts to quit. One friend eventually refused to see me until she had completely rid herself of the habit. I was so ashamed that I followed suit pretty quickly. It's a pretty common story with lots of behaviours, from cigarettes to alcohol to food.

    Anybody who thinks they're not influenced by the people around them, or thinks that it all comes down to personal will power alone, doesn't understand group dynamics. - 7/5/2011 4:55:50 AM
  • RAERAEMCRAE
    Postcript: The word "MAKING" in the title is just a lead-in, an attention grabber. The article nowhere states that we have no choice and that our friends are 'creating" us. In fact, it states just the opposite. We can take positive steps that will reverse the trend in our social circle. - 6/19/2011 11:09:35 PM
  • RAERAEMCRAE
    I felt a little sad reading some of the pained responses to this article. It seems like some of us might feel a little scared of being rejected as a friend because of the truth found in it. I think most of us know at heart that it makes sense, but it's hard to face, particularly if we've been discriminated against before. Yet, it is so vital not to allow ourselves to resent realities because they hurt our feelings.
    I have personally experienced this particular statistical reality several times, when moving cities or social circles. I am driven (and facilitated by their good habits) to get thinner when I am with thinner friends. They make comments on my choices and kindly but frankly confront me on them. They are also very physically active, and if I want to be with them, I need to keep up.
    These factors are all possible with overweight people, as well, but outside of places like SparkPeople or other programs, it seems rare.
    Conversely, I excuse myself and feel "relatively thin" when I am with heavier friends, even when my own weight starts to creep up. It becomes easier to gain weight, because so many of our activities involve food, and they often are not interested in my new "exercise kick". I see them eat dessert each meal and feel it is only natural and right to do the same.
    The positive takeaway from this article is that, no, that is NOT an excuse! Yes, we are still responsible for our own behaviors, provided we become educated and conscious of them. Once we "know better", we are obliged to help ourselves. And others!
    That is why we are all here at SparkPeople. Anyone here is taking steps to do just that. Bravo!
    Not ALL overweight people are currently inactive and overeat. But barring disease and health crises, the majority of overweight people have gotten there through bad habits, which spread easily.
    1 Cor. 15:33 says, "Do not be misled. Bad associations spoil useful habits."
    In this case, it's not the actual associates who are bad.
    It is the habits. - 6/19/2011 11:06:44 PM
  • Regardless of all our qualms about beating peer pressue, there have been multiple scientific studies to reinforce this type of thing. It's not a difficult study to perform, and it can be applied to pretty much any social behavior from dialect to crime rates to food to smoking to drinking. It may sound like bogus, but peer pressure exists. Having chubby friends makes it more ok for us to be chubby. Call it what you want, but statistics don't lie. - 3/15/2011 1:08:09 PM
  • I can see that social behaviors could cause one to become obese...but really...don't blame me for you getting fat if you do become obesed!!.....I am obesed from a disease (hypothyroid) and my children and husband are all within respectable weights.....all my friends are in respectable ranges....key factor is...no one can make you eat or do something you don't want...it's a matter of choice and a free will. Everything is based on choices or free agency (as I call it). Harvard really needs to focus their fundings on more important studies like how to prevent or find a cure for the many different cancers out there. - 2/19/2011 2:23:20 AM
  • This is the most insane thing I think I have heard in a long time. It must be a study that was funded by governmental pork! So, what ever happened to taking responsibility for ones own life? that just flew out the window . . . - 1/10/2011 7:47:37 AM
  • Overweight people do not make other people fat. No one can force anyone else to overeat. People make their own decisions and they are the ones who need to be responsible for the consequences of their decisions. Personally, I'm really tired of all this nonsense where people blame others for their poor decisions. Seriously! People just need to take responsibility for their own decisions. The lack of personal responsibility in our society is shocking. This kind of "study" just helps people play the "blame game" and avoid being responsible for themselves. It also helps people to justify discrimination against those who are overweight. I'll bet that a lot of people have decided to dump their overweight friends or to avoid making friends with overweight people just because of this "study." I can just hear these people saying stuff like, "I can't be friends with fat people because their fat is catching...there'
    s even a study that says so." Give me a break. - 11/3/2010 3:22:27 PM