The Obesity Era


David Berreby in Aeon Magazine:

[T]he scientists who study the biochemistry of fat and the epidemiologists who track weight trends are not nearly as unanimous as Bloomberg makes out. In fact, many researchers believe that personal gluttony and laziness cannot be the entire explanation for humanity’s global weight gain. Which means, of course, that they think at least some of the official focus on personal conduct is a waste of time and money. As Richard L Atkinson, Emeritus Professor of Medicine and Nutritional Sciences at the University of Wisconsin and editor of the International Journal of Obesity, put it in 2005: ‘The previous belief of many lay people and health professionals that obesity is simply the result of a lack of willpower and an inability to discipline eating habits is no longer defensible.’

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. The marmosets gained an average of nine per cent per decade. Lab mice gained about 11 per cent per decade. Chimps, for some reason, are doing especially badly: their average body weight had risen 35 per cent per decade. Allison, who had been hearing about an unexplained rise in the average weight of lab animals, was nonetheless surprised by the consistency across so many species. ‘Virtually in every population of animals we looked at, that met our criteria, there was the same upward trend,’ he told me.

It isn’t hard to imagine that people who are eating more themselves are giving more to their spoiled pets, or leaving sweeter, fattier garbage for street cats and rodents. But such results don’t explain why the weight gain is also occurring in species that human beings don’t pamper, such as animals in labs, whose diets are strictly controlled.