Are your friends making you fat?

Is your social circle making you fat? There are a number of triggers for weight gain that many women never consider.

Love is probably not the first thing that springs to mind when you're looking for somewhere to lay the blame for a bout of weight gain. But research has shown that all your relationships, from your significant other to your platonic friendships, can influence your weight. Think it sounds crazy? You might be surprised.

Diet flashpoint: Getting married

Both men and women are twice as likely to pile on the kilos when they marry as people who are just dating. A University of North Carolina study also found that, for women, even just cohabiting with a partner made them 63 per cent more likely to put on weight.

Dr Lauren Williams, from the University of Newcastle, says: "Sociologically, we're no longer trying to attract a mate after we've settled down, so that can have a negative effect on our desire to maintain what we see as an 'attractive' weight."For women, living with a man can mean eating more than we're used to. "We get used to serving and eating bigger meals, or eating dessert regularly, and without an increase in physical activity, that can result in weight gain," says Dr Williams.

Diet flashpoint: Starting a family

While you'll obviously put on weight when you fall pregnant, you might be surprised to learn that your partner probably will too - about 6.35 kilograms on average, according to a British survey conducted lastyear.The reason for the gain in girth? Respondents listed reasons such as snacks being more readily available and being served larger meals by their pregnant partners.

Unfortunately the survey also found that only 30 per cent of the men who gained weight tried to shed it once the baby was born.

Diet flashpoint: Ending a relationship

For females, a break-up can spell bad news for our weight, but not so for men, with UK researchers finding that women tend to gain weight when they end a relationship, but men don't. The researchers suggest it's because women are more likely to turn to food to deal with emotional stress.

Diet flashpoint: An overweight friend

A US study published in 2007, which tracked more than 12,000 people over a 32-year period, found that your chances of becoming overweight increase by a whopping 57 per cent if you have a friend - particularly a same-sex friend - who is overweight. A similar 2008 study found that, without being aware of it, people tend to "keep up with the Joneses" when it comes to weight.Clinical health psychologist Dr Leah Brennan says the fact that Australians are bigger than we used to be doesn't help. "We have a new 'normal' in terms of which body weights are acceptable. People also tend to have an image of what they consider overweight or obese, and as long as they're smaller than that, it's easy to think they're okay."

Diet flashpoint: Overweight sibling

The same US study discovered that, among adult siblings, if one becomes obese, the chance that the other will follow in their footsteps increases by 40 per cent. The familial link to obesity is well established. A 2004 Stanford University study found having overweight parents put children at the greatest risk of being overweight, and a British study released in 2009 found that obese mums were 10 times more likely to have obese daughters, while obese dads were six times as likely to have obese sons.

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