Obesity or weight loss contagious? It can happen, and it does

Just what everyone wanted to know. A 32-year study has found that social patterns, even at a distance, can affect weight. If a person becomes obese, that person’s friends tend to become obese, too.

Weight loss shows the same effect, but most of the effects studied were of obesity. This information comes from no less an authority than the Harvard Medical School. Professor of medical sociology Nicholas Christakis makes the point in this New York Times article that the perception of acceptable body size changes if one’s friends become obese. The effect extends through an individual’s social networks. Results were variable over the samples, and consistency is debated, not entirely surprisingly, by Yale obesity researchers, who consider that the obese are likely to be blamed for environmental factors. Genetic factors are also involved, and in any group of samples a bit of nitpicking about quality is pretty normal, and highly relevant in some cases. Atypical samples can skew results. The Harvard research, however, has raised the bar in terms of research methods, at least. The depth of the research and the period of coverage is unique, and the scope of coverage stemmed from an ongoing heart disease study, which provided the necessary data, and the social ranges. I think readers should have a look at the data and the interpretations here, because this is no simple subject. People’s lives do, and will, depend on how good the medical research into obesity is. Those living with the problem aren’t too keen on guesses, either. The question now is how to duplicate the results for clinical verification and exploration of possible benefits. It won’t be easy, but it would be worth it. Nobody’s debating the effects of obesity. Socially, it’s a big issue, and getting bigger.