Obesity isn’t just a problem in the developed world, it is a global (and, indeed, globular) crisis. We must, of course, resist the temptation to make light of this issue, because the implications are deadly serious – as David Berreby reminds us in a startling article for Aeon:
- “For the first time in human history, overweight people outnumber the underfed, and obesity is widespread in wealthy and poor nations alike. The diseases that obesity makes more likely — diabetes, heart ailments, strokes, kidney failure — are rising fast across the world, and the World Health Organisation predicts that they will be the leading causes of death in all countries, even the poorest, within a couple of years.”
Furthermore, the financial costs of the obesity epidemic will fall on taxpayers of all shapes and sizes:
- “…the long-term illnesses of the overweight are far more expensive to treat than the infections and accidents for which modern health systems were designed. Obesity threatens individuals with long twilight years of sickness, and health-care systems with bankruptcy.”
Who’s to blame for this crisis? Some people say the food and drink industry, while others insist that obesity is obviously the fault of obese people. Alternatively, one can target both the producers and the consumers of fattening products:
- “As the Mayor of New York, Michael Bloomberg, recently put it, defending his proposed ban on large cups for sugary drinks: ‘If you want to lose weight, don’t eat. This is not medicine, it’s thermodynamics. If you take in more than you use, you store it.’ (Got that? It’s not complicated medicine, it’s simple physics, the most sciencey science of all.)”
Individuals should, of course, take responsibility for their own health – but what if there's more going on here than a simple failure of personal restraint?
- “Consider, for example, this troublesome fact, reported in 2010 by the biostatistician David B Allison and his co-authors at the University of Alabama in Birmingham: over the past 20 years or more, as the American people were getting fatter, so were America’s marmosets. As were laboratory macaques, chimpanzees, vervet monkeys and mice, as well as domestic dogs, domestic cats, and domestic and feral rats from both rural and urban areas. In fact, the researchers examined records on those eight species and found that average weight for every one had increased.”
Is this just a case of fat people having fat pets – or feral animals growing fat on all the food we throw out? The fact that laboratory animals are getting fatter too would indicate that something else is at work:
- “…lab animals’ lives are so precisely watched and measured that the researchers can rule out accidental human influence: records show those creatures gained weight over decades without any significant change in their diet or activities.”
It is sometimes argued that social factors such inequality and sexism are to blame for the rise in obesity. However, it’s unlikely that such concerns impact greatly upon the lives of marmosets and laboratory mice. Rather, if the evidence on weight gain across species really does stand up, then an environmental factor would seem to be involved:
- “Viruses, bacteria and industrial chemicals have all entered the sights of obesity research. So have such aspects of modern life as electric light, heat and air conditioning. All of these have been proposed, with some evidence, as direct causes of weight gain: the line of reasoning is not that stress causes you to eat more, but rather that it causes you to gain weight by directly altering the activities of your cells.”
It isn’t unreasonable to suppose that at least one of the countless changes we’ve made to our environment is exerting an influence on human (and animal) metabolisms. Furthermore, the effect doesn’t need to be a very large one. As David Berreby points out “eating a mere 30 calories a day more than you use is enough to lead to serious weight gain.”
Food for thought.