Obesity is less common in more equal societies.
Obesity is increasing rapidly throughout the developed world. In some countries rates have doubled in just a few years. In the USA, three-quarters of the population are overweight, and close to a third are obese. In the UK, two-thirds of adults are overweight and more than a fifth are obese. Obesity increases the risk of hypertension, late onset diabetes, cardiovascular disease, gallbladder disease, and some cancers. The trends in children's obesity are likely to lead to shorter life expectancies for today's children - this would be the first reversal in life expectancy since the nineteenth century.
We found that obesity among men and women (see graph), as well as calorie intake and deaths from diabetes, are related to income inequality in rich countries. In addition, obesity in adults is also related to inequality in the 50 US states; and the percentage of children who are overweight is related to inequality both internationally and in the USA.
Pickett KE, Kelly S, Brunner E, Lobstein T, Wilkinson RG. Wider income gaps, wider waistbands? An ecological study of obesity and income inequality. Journal of Epidemioogy and Community Health 2005;59(8):670-4
The International Obesity TaskForce http://www.iotf.org/
World Health Organization http://www.who.int/topics/obesity/en/
Wilkinson RG, Pickett KE. The Spirit Level. Penguin. 2009. Buy the book from Amazon.