How income inequality leads to obesity

Modern life is perhaps conspiring to make us fat, suggest Richard Wilkinson and Kate Pickett in ‘The Spirit Level: Why more equal societies almost always do better’ (www.landmarkonthenet.com). In the past the rich were fat and the poor were thin, but in developed countries these patterns are now reversed, they add.

A study cited in the book is of the World Health Organisation, which found the steeping of social gradient as rates of obesity have increased. “By the early 1990s obesity was more common among poorer women, compared to richer women, in all 26 countries, and among poorer men in all except five.”

The sudden rapid increase in obesity in many societies cannot be explained by genetic factors, the authors aver. “People often point to the changes in cost, ease of preparation and availability of energy-dense foods, to the spread of fast-food restaurants, the development of the microwave, and the decline in cooking skills. Others point to the decline in physical activity, both at work and in leisure time, increasing car use and the reduction in physical education programmes in schools.”

But the real culprit may be income inequality, the book postulates. Scatter diagrams that plot income inequality on the x-axis and per cent obese on the y, show a preponderance of obesity, both among adults and children, in the more unequal US states.

Calorie intake and exercise are only part of the story, note Wilkinson and Pickett. “People with a long history of stress seem to respond to food in different ways from people who are not stressed. Their bodies respond by depositing fat particularly round the middle, in the abdomen, rather than lower down on hips and thighs.” Quite alarmingly, people who accumulate fat around the middle are at particularly high risk of obesity-associated illnesses.

Apart from the addition of weight in the worst places, stress can cause us to increase our food intake and change our food choices, a pattern known as stress-eating or eating for comfort, the authors report. “In experiments with rats, when the animals are stressed they eat more sugar and fat… In a study in Finland, people whose eating was driven by stress ate sausages, hamburgers, pizza and chocolate, and drank more alcohol than other people.”

Scientists are starting to understand how comfort eating may be a way we cope with particular changes in our physiology when we are chronically stressed, changes that go with feelings of anxiety, the authors inform. “Recent research suggests that food stimulates the brains of chronic over-eaters in just the same ways that drugs stimulate the brains of addicts.”

A chapter titled ‘Building the future’ forecasts that the proportion of the population feeling they could trust others might rise by 75 per cent in the US, if only the country’s inequality were reduced to something like the average of the four most equal of the rich countries (Japan, Norway, Sweden and Finland).

The authors foresee, then, matching improvements in the quality of community life; “rates of mental illness and obesity might similarly each be cut by almost two-thirds, teenage birth rates could be more than halved, prison populations might be reduced by 75 per cent, and people could live longer while working the equivalent of two months less per year.”