Yesterday dietitian Susie Burrell made the extraordinary claim that obesity is socially contagious in an opinion piece titled ‘Wanna get skinny? Might be time to ditch your fat friends’.
Burrell cited the Framingham Heart Study as evidence that people who have fat friends are more likely to become fat themselves. She called for readers to avoid fat people, lest they become infected with this modern-day social contagion.
This is so messed up I don’t even know where to begin.
The Framingham Heart Study was a decades-long analysis of heart disease that started in 1948 in a Massachusetts town.
Nearly 40 years later, ‘social contagionist’ scientists from Harvard Medical School and the University of California dredged up the old data and performed statistical analysis, concluding that obesity is socially contagious.
The same authors have made claims in the New England Journal of Medicine and various media outlets that everything from obesity to divorce to poor sleep to loneliness is also socially transmissible.
Their conclusions have since met widespread criticism.
In a paper titled ‘The Spread of Evidence-Poor Medicine via Flawed Social Network Analysis’, the mathematician Russell Lyons reported the statistical methods used by lead author Nicolas Christakis and James Fowler to be riddled with statistical errors on many levels.
Lyons’ paper has since passed peer review and was published in the journal Statistics, Politics, and Policy. A PhD candidate at the Sociomedical Sciences at Columbia University’s School of Public Health, David Merritt Jones, has been keeping a close eye on the developments as they unfold. He reports:
Two other recent papers raise serious doubts about their conclusions. And now something of a consensus is forming within the statistics and social-networking communities that Christakis and Fowler’s headline-grabbing contagion papers are fatally flawed.
Andrew Gelman, a professor of statistics at Columbia, wrote a delicately worded blog post in June noting that he’d ‘have to go with Lyons’ and say that the claims of contagious obesity, divorce and the like ‘have not been convincingly demonstrated’.
Another highly respected social-networking expert, Tom Snijders of Oxford, called the mathematical model used by Christakis and Fowler “not coherent.” And just a few days ago, Cosma Shalizi, a statistician at Carnegie Mellon, declared, ‘I agree with pretty much everything Snijders says’.
Gelman argues that the papers might not have been accepted by top journals if these technical criticisms had been aired earlier. Indeed, Lyons posted damning quotes from two anonymous reviewers of his own work. “[Christakis and Fowler's] errors are in some places so egregious that a critique of their work cannot exist without also calling into question the rigor of review process,” one of them wrote.
Christakis and Fowler have since been invited to provide an explanation of their statistical methods in the journal Annals of Applied Statistics. However, as of July 2011, this was reportedly still being revised.
It is difficult to understand why Burrell would rehash such a highly contested study and use its dubious findings to call for the hysterical and widespread discrimination against fat people.
The title of Burrell’s piece is alarming. It assumes that being skinny is what readers of The Punch either already desire or should desire to achieve.
Burrell goes on to promote stereotypes, associating ‘overweight’ with morally deficient characteristics such as laziness, while encouraging readers to seek out “thin, fit and healthy” people and “do what they do”.
Does it really need to be spelled out that not all fat people are automatically lazy, gluttonous slobs? That being “fit and healthy” is not exclusively synonymous with being thin? That we cannot assume that just because as person is thin they are engaging in healthy behaviours, or because they are fat, they are eating cheese puffs all day?
With approximately 70 per cent of our DNA contributing to our weight, why does Burrell assume everyone should – and can be – thin?
Burrell concludes that if a fat person expresses concern about their friend’s gym habits, the friend should ‘defriend’ the fat person and tell them they are ‘disappointed’ with them.
What if the fat person’s friend engages in compulsive exercise? Or is suffering from an eating disorder and really should not be exercising four hours a day? Does it really make sense to make these broad sweeping generalisations and recommendations?
Burrell’s claim that “dieting is frowned upon by those who know they too need to lose weight, but are currently making the choice not to” is grossly misleading. It is absurd to suggest that only fat people who need to lose weight are against dieting.
Numerous studies since 1959 have shown diets for weight loss carry a failure rate of 95-98 per cent after 2-5 years.
Health writer Paula Goodyer attempted to demonstrate weight loss as sustainable in an article titled ‘The Exercise Myth’ last week in The Sydney Morning Herald by citing The National Weight Control Registry which supposedly proves people can lose weight and keep it off over the long term.
Yet this registry was discredited by dietitian Joanne Ikeda and her team of researchers as far back as 2005.*
Diets don’t work, and carry unintended consequences that put a person’s health at risk. These include food and body preoccupation, weight cycling, higher than pre-diet starting weight, eating disorders, weight stigmatisation, and binge eating.
It is unethical for a health professional to recommend the discrimination and stigmatisation of fat people. It goes against the very spirit of health to promote anything that actively harms a population of people. Research has shown that shame does not lead to health-giving behaviours.
The best thing we can do for our health is focus on health-giving behaviours, and allow our weight to fall where it will.
Already a global shift away from a weight-based approach to a health-centred paradigm is happening – with the key principles including finding pleasurable physical activity, engaging in intuitive eating, and viewing health as a multi-dimensional, ongoing process including physical, intellectual, social, emotional, spiritual, and occupational aspects.
*see Ikeda et. al. (2005). The National Weight Control Registry: A Critique. Journal of Nutrition Education and Behavior, 37(4): 203-205.
Note: In response to readers’ feedback, the source of the 70 per cent statistic can be found here. What this means is that approximately 70 per cent of the outcome in weight variability in a population can be attributed to genetic causes.