Julian Sheather on fat and human freedom

It was the White Queen who told Alice that she had at times thought six contradictory things before breakfast. We humans have a remarkable tolerance for incompatibility, happily living with any number of self-cancelling beliefs about ourselves and the world. So difficult is it to imagine – or at least for me to imagine – what an entirely coherent set of beliefs would look like that I’m tempted to think it impossible, something best left for angels, or even, hallowed be their name, philosophers.

Although we all surely have an inalienable right to contradict ourselves in the comfort – or otherwise – of our own minds, things get a little trickier when it comes to public policy. For a while now I’ve been brooding on the paradoxes of public health interventions. Remember the Foresight report from 2007: Tackling Obesities: Future Choices? (Just as an aside – why obesities? To what do we owe that knowing plural? Are we about to enter a whole new world of overweightness? To encounter hitherto undreamt of ways of being stout? Apparently not. According to the executive summary it is an attempt to capture the “multi-dimensional” origins of obesity).  Cringeworthy plurals aside, the main drift of the report is that we need to set aside the timeworn view that people put on weight because they make a choice to eat too much.

Instead we need to see the ballooning levels of obesity as the result of a combination of genetic and environmental factors. Our evolution in the wild has predisposed us to store energy as fat during times of plenty in order that we can survive during leaner times. Unfortunately for our western waistlines there are now no lean times. The conditions of life have changed beyond recognition and the combination of permanent plenty, and the sedentary lives bequeathed to us by modern ways of travelling and working, have sprung the twin jaws of a public health trap into which our maladapted bodies are blundering.

There is a fairly obvious sense in which this just must be true. The physics of weight gain are quite straightforward. If we take in more energy than we consume we store the energy as fat and put on weight. If food is not available, or if we consume it through necessary physical activity, then we don’t put on weight.

But if the environmental picture is true, and I believe that it is, how do we account for those who do not put on weight, for the two or three out of every four who do not consume more energy as food than they expend in exercise? After all, we all swim in the same “obesogenic” sea.

Like all of us, I know fat people and I know thin. The thin ones eat less and exercise more than the fat ones. They choose to do this, at least in so far as human beings choose to do anything. So up against the truth that our environment makes us fat must be set the truth that our weight is the result of choices that we make. Both of these truths speak to deep intuitions we have about human behaviour. The problem is that at some level these truths seem to be incompatible.

From one angle the problem is a newish nibble on a very old doughnut, the question of whether our actions issue from our free will, or whether they are determined by the effects of pre-existing conditions working through ineluctable natural laws. From another albeit related angle it is also a question of perspective.

At an individual level, and to a greater or lesser extent, each of us wrestles with our own appetites. It always feels like a deeply personal struggle: to yield or to resist; to eat or not to eat. Pull back a little though, use a wider angle lens, look not at the struggle in an individual soul, but at groups of us wrestling en masse, and the picture changes.

At this level shared human traits will tend to express themselves in similar ways. And so while it may never be possible to judge the outcome of each individual struggle, broader outcomes look more predictable. While we all make our own choices, stuff the supermarket aisles with cheap calorific food, bring in mechanical transport, and a rise in levels of obesity seems almost inevitable.

Two truths then, truths that are in some ways linked and in others in opposition. We all make our own decisions about what to eat, but we swim in currents that can incline us in certain directions. We seem to be both free and under the strong influence of circumstance. Perhaps the biggest challenge confronting public health is how to speak coherently to both these truths at once.

Julian Sheather is ethics manager, BMA. The views he expresses in his blog posts are entirely his own.

  • Les Simpson

    Julian Sheather’s thoughts about obesity reflect medical opinons concerning body weight. In 1949 when studying physical anthropology, we were introduced to somatypes – body forms – but the implications have never been adopted by the medical fraternity.
    Although William Sheldon’s 1940s concept of 3 somatypes – ectomorph (individuals who were tall and thin with long limbs and low fat storage); mesomorph (individuals who had the capacity to increase muscle mass with low fat storage); and endomorph (individuals with a large body size and with increased fat storage); has not gained general acceptance, there is little difficulty in sorting out ectomorphs, for example. Most people will have a friend or relative who is tall and slender, with no any apparent limitations on food intake without an increase in bodyweight. In my experience, such people also have a great difficulty in
    increasing muscle mass, by weight training, for example.
    The muscular development of bodybuilders typify mesomorphs while Samoans and Tongans appear to characterise endomorphs.

  • Side-by-side with Les Simpson’s experience in the study of anthropology, we should consider the endocrine causes of obesity e.g.the oestrogen-progestogen formulations in the Oral Contraceptive pill causes obesity in some women but not in others, how so? Likewise, systemic cortico-steroid use causes obesity in many men and women, not every user of this drug, how so? and so on.
    Obesity is not simplistically caused because of excess intake of food and beverages, rather the type of food and drink that is consumed, in addition to the quantity.

  • I can’t resist being pedantic and pointing out that in response to Alice’s comment “One can’t believe impossible things” the White Queen actually said
    “I dare say you haven’t had much practice … When I was your age, I always did it for half an hour a day. Why, sometimes I’ve believed as many as six impossible things before breakfast.” I only know the exact wording because I use the quote when I’m teaching courses on critical appraisal. But in a shameless link to my own blog (http://blogs.bmj.com/bmj/2009/09/07/liz-wager-itll-only-take-5-minutes/
    ) I wonder if that’s something else I’ve got to do for 30 minutes each day …
    but you make a good point (even if you have slightly misquoted one of my heroes!)