A group of researchers at Harvard Medical School have come up with a theory that is making a lot of people sit up and take notice. After a great deal of research involving over 12,000 people they have come to the conclusion that obesity is contagious. This doesn't mean that you're going to start putting on the pounds after sitting next to an overweight person in an airplane. There's a bit more to it than that.

What they've discovered is that there is a causal relationship that is at the bottom of this phenomenon. It is not that obese people deliberately find other obese people to be with, it's more that people's idea of what might be an acceptable weight goes through a process of change when in the company of obese or overweight people. This may well be a sub-conscious reaction, but allows people to feel that it's okay to overweight.

For the first time obesity has been put into a social context. If everybody is carrying too much weight then it's easy to see why people are not concerned by their body weight. In fact many probably take comfort from the fact that they are no different to anybody else. If not in a 'club', they are certainly not made to feel that they need to make change - probably completely the opposite.

One aspect of the study which attracted some attention was that obesity could still have a contagious effect between friends even although they didn't come into regular contact. Influence obviously being more important than either the environment or lifestyle.

It is clear that the current obesity crisis has been exaserbated by the social dimension. In fact it could well account for the rapid rise in obesity in recent years.

Is there a danger that being obese or overweight will be the accepted norm? If it is socially acceptable then there will be less and less pressure to change efforts to assist those who want to make change will diminish. The effect on the nation's health and on healthcare costs is likely to be significant - and we'll have a nation full of very unhappy, immobile, unhealthy old people. Not a great thought.

It's not all gloom and doom though. If obesity is contagious, there is no reason why being slim can't be contagious too! A 'slimness' epidemic is perfectly possible, but would it be difficult to sell? If feeling a million dollars, being physically able to do whatever you want to do, being happy, being on top of your job and in good health is hard to sell we should all pack our bags now! It's time to get the slim habit!