Professor David Matthews (OCDEM) and Katy Cooper (OxHA) respond to Yach et al., 'Epidemiological and economic consequences of the global epidemics of obesity and diabetes' in Nature Medicine 12(1), January 2006.
In their analysis of the economic consequences of the global epidemic of obesity and diabetes (Nature Medicine 12(1), 62 (2006)) Yach, Stuckler and Brownell focus on the complexity of making successful interventions. They codify this, somewhat opaquely, as relating to i) ‘externalities’, ii) ‘imperfect and asymmetric information’ and iii) ‘time-inconsistent preferences’. Such language does not help to clarify the problem, but illustrates its difficulty. How do we persuade society and individuals to implement change in lifestyle?
Only interventions that are applied simultaneously at many levels are likely to succeed, as has been well illustrated by the story of society coming to grips with the tobacco industry. But control of obesity is much more complicated – no one should smoke, but we all need food. We die rapidly with too little food, and slowly from cardiovascular or other pathology, including diabetes, with too much food. Nor is the epidemic simply related to food intake – the evidence is that obesity is also predicated on a lack of physical exercise. Exhortation from professionals may help, but is often ignored. Verbal agreement of a patient with the professional is common, but change of habit is rare – there is always some excuse, from the failing health of the dog (hence no exercise) to stress (hence overeating).
Nevertheless, we do not need more research into the precursors of obesity. The physics and metabolism is straightforward – weight increase is a function of calorie intake and calorie expenditure. Can we change the balance? Reducing calorie intake can be achieved by dietetic interventions, but these are often successful only in the short term. In the longer term it is likely that we will need a concerted effort to improve calorie labelling on food, to run educational and entertaining educational initiatives, to change the culture of ‘clearing the plate’, to reduce fat (high-calorie) content of food, to alter attitudes to snacks (fruit is preferable to chocolate biscuits) and so on. This illustrates that multiple interventions will be required. Government could insist on visible calorie labels on food comparable to the size of warnings on cigarette packets, for example. We could encourage the culture of ‘eat for your need and not for your greed’; we can increase the availability of fruit and low-carbohydrate drinks; we can cheer the food industry when it focuses on diversifying into healthier options. Physical exercise not only means work-outs in the gym: it means encouraging walking to work, and cycling, and gardening, and using stairs – and just simply getting off our backsides more often. It is an indictment of our society that people do not walk up escalators, that the only stairs in hotels are fire escapes and that driving very short distances is becoming increasingly common. Multiple interventions here would mean a change in our urban and building planning to promote a healthy society.
The tragedy of the diabetes and obesity epidemic is not that we don’t understand it – we do! The tragedy is that society and individuals do so little about it.
David Matthews and Katy Cooper, 12 January 2006
