Australasian Science: Australia's authority on science since 1938

Choose Your Friends Wisely

By Tim Olds

Friends, family and co-workers influence our health and happiness to varying extents.

The full text of this article can be purchased from Informit.

When asked about what one could do to improve one’s fitness, the renowned exercise physiologist Per-Olof Åstrand replied: “Choose your parents wisely”. Now it seems that to improve our health we have to do more than choose our parents: we need to choose our friends because disease (and health) can spread through our real and virtual social networks.

One US study that followed 12,000 people for 32 years found that your risk of becoming obese increases by about 40% if you have a sibling or spouse who becomes obese ( The important factor is social distance (e.g. being the friend of a friend) rather than geographical distance. You won’t become obese if the people next door you never speak to become obese, but if your best friend on the other side of town fattens up, you’re more likely to put on the kilos as well.

The love also has to be mutual. Your risk of obesity is unaffected if your soon-to-be-obese acquaintance considers you a friend but you don’t. If you consider them a friend, but they don’t consider you a friend, your risk goes up by 57%. If you both consider each other friends and your friend becomes obese, your chances of becoming obese nearly treble (171% increased risk). It may be time to find that “unfriend” button on Facebook.

Even death...

The full text of this article can be purchased from Informit.