The truth about whether your friends are making you fat
Be careful how you choose your social circle as obesity can be ‘catching’, scientists warn. reports
Why do you think you’re fat? It might not just be because you eat too much and exercise too little. Try this excuse for size: according to research, if you’re trying to stay in shape, you might want to avoid certain friends because scientists have discovered that your figure is connected to the company you keep. And, perhaps more shockingly, to the shape that your friends’ friends are in, too.
A growing body of evidence suggests that, improbable as it may sound, we can “catch” both obesity and weight loss from our social circle.
A study published in the journal JAMA Pediatrics, which looked at thousands of US military families, found that, when assigned to bases in communities with higher rates of obesity, residents were more likely to become overweight or obese, compared with families sent to areas where the locals were more svelte.
For every single percentage-point increase in the local obesity rate, the odds that a teenager would be overweight or obese went up by four to six per cent, while the odds that a parent would be obese went up by five per cent.
What’s more, the longer and more closely that the families were “exposed” to their surrounding community – by living there for more than two years, or living off-base with the locals – the more likely they were to “catch” this weight gain.
“Social contagion in obesity means that if more people around you are obese, then that may increase your own chances of becoming obese,” explained Ashlesha Datar, one of the authors of the study, conducted by the University of Southern California. “Subconsciously, you are affected by what people around you are doing. If you move to a community where a sedentary lifestyle is the norm, you join that. There is this social influence.”
This may sound extraordinary and unlikely, but a slew of other studies have all pointed in the same direction. In 2007, Prof Nicholas Christakis, an early researcher into weight contagion, and his colleagues at Harvard Medical School examined data from the Framingham Heart Study, one of the biggest medical investigations ever conducted, which followed 12,000 people over 32 years, accumulating detailed information about participants’ health, weight and where they lived. To general amazement, researchers found that if a friend becomes obese, your own chances of piling on the pounds rises by a whopping 57 per cent.
Even more astoundingly, the same research found that if a friend’s friend became obese, your risk rose by 25 per cent; indeed, your risk rose if a friend’s friend’s friend became obese – by 10 per cent. In other words, a complete stranger could be causing you to burst out of your clothes.
However, local environmental influences didn’t quite explain all of Prof Christakis’s findings. His researchers found that emotionally close friends who lived hundreds of miles away were more influential on each other’s weight than casual friends that lived next door.
Prof Christakis, who now runs the Human Nature Lab at Yale University and is the author of Connected: The Amazing Power of Social Networks and How They Shape Our Lives, says: “It is not literally the obesity that spreads, but norms and behaviours [around eating and exercise].” In other words, you might adopt a fatter friend’s habits, like diving into the bread basket when you might once have waved it away.
Last year, diet club Slimming World
Leah Hardy
got into trouble for suggesting that successful slimmers might want to shun chubby chums to help keep the weight off. A plus-size blogger was horrified to find that a newly slender friend had been given a book of advice on how to maintain her new body. It recommended reshaping your social life, with the advice: “Spend less time with overweight friends.”
And it’s not just weight-gain that can be catching. Last year, a study by the University of Michigan found that flu sufferers with weight issues were contagious for longer than their slimmer peers.
Fortunately, the influence isn’t all one way. In an earlier study, published in 2016 in the journal Obesity, Prof Christakis found that people who wanted to lose weight were more likely to shed pounds if they increased “contacts and interactions with thinner individuals” and had
“declining contacts and interactions with heavier individuals”.
Prof Christakis says this could be down to those subconscious influences again. “A person who starts jogging may influence his friend to take up swimming or reduce eating, and both individuals may lose weight as a result,” he says.
Similarly, researchers based at the University of Connecticut last year found that if one half of a couple decides to diet, the other has a good chance of losing weight, too, even if they’re not actively participating in it. The study tracked the weight loss of 130 couples over a six-month period and found that more than a third of partners lost at least three per cent of their body weight if their significant other was actively trying to slim down. That was true even if they weren’t trying to lose weight themselves.
Prof Amy Gorin, the study’s lead researcher, dubbed it “the ripple effect”. “When one person changes their behaviour, the people around them change,” she says.
Nutritionist Kim Pearson has seen the social contagion effect first hand. “I have shrunk many of my friends, as well as my clients,” she says. “Although I’m a size eight, I gain weight easily and could be much bigger if I didn’t exercise and be mindful of what I eat. I think my friends see that if I can be slim and healthy, they can be, too.”
So many friends asked Pearson, 34, for help with managing their weight that two years ago she set up a Whatsapp motivational group with three of her closest friends and her sister. One of those friends, Louise
Bryant, 38, a mother-of-three and trainee life coach, lost two stone, dropping from a size 14 to a size 8-10.
Bryant says: “We all follow the dietary principles devised by Kim. But more than that, we speak every day, set goals together, and have supported each other through all our ups and downs in life, including times when we could reach into the fridge to make things better. We often show each other pictures of our meals, so when I look at a menu, I think: ‘If I’m going to share this with the girls, it had better be a healthy choice’.” She adds: “Despite the fact that we live miles apart, I feel surrounded by likeminded people who care.”
But these success stories don’t mean that if you want to see less of yourself you must see less of your friends. Prof Christakis says: “Even if it is true that avoiding overweight friends might help stop any social contagion in obesity, this benefit would come at the cost of losing a friend. This is not a good thing for our health in general, or our lives, as having friends is not only one of life’s great pleasures, but also crucial to our well-being. While avoiding your friends who are bank robbers might be good advice, avoiding your friends who are overweight is not.”
The key to staying in shape without shrinking your social circle is to take charge. Dr Meg Arroll, a psychologist and co-author of The Shrinkology
Solution, about the psychology of eating and weight loss, says: “People have a strong tendency to mirror each other’s behaviour, especially around food. It is a non-verbal form of empathy and important in forming bonds. But just because a friend has gained weight, it doesn’t mean you have to as well.”
Dr Arroll says much of our behaviour around food is subconscious, so if your weight is creeping up, she suggests you should keep “a mood and food diary”, in which you write down everything you eat, how you felt when you ate it and, crucially, who you ate it with. “People usually quickly spot patterns emerging, including how you influence each other,” she says. “By deliberately choosing to eat well and exercise, you can be the stone that causes a ripple effect, helping others to become healthier.”
‘If more people around you are obese, that may increase your own chances’