Bigger Isn't Better When it Comes to BMI

The Economist this week dovetails with the special issue of the Lancet devoted to the new findings from the Global Burden of Disease project. That analysis suggests that we're living longer, but sicker. A key ingredient in the sicker part is obesity and the Economist has a special section devoted to this topic, referencing researchers involved in the Global Burden of Disease project.

Two-thirds of American adults are overweight. This is defined as having a body mass index (BMI, a common measure of obesity) of 25 or more, which for a man standing 175cm (5’9”) tall means a weight of 77kg (170 pounds) or more. Alarmingly, 36% of adults and 17% of children are not just overweight but obese, with a BMI of at least 30, meaning they weigh 92kg or more at the same height. If current trends continue, by 2030 nearly half of American adults could be obese.

The rest of the world should not scoff at Americans, because belts in many other places are stretched too, as shown by new data from Majid Ezzati of Imperial College, London, and Gretchen Stevens of the World Health Organisation (WHO). Some continental Europeans remain relatively slender. Swiss women are the slimmest, and most French women don’t get fat, as they like to brag (though nearly 15% do). But in Britain 25% of all women are obese, with men following close behind at 24%. Czech men take the European biscuit: 30% are obese.

In a few places obesity rates seem to be levelling, but for now waistlines in most countries continue to widen unabated. Jiang He and his colleagues at Tulane University have estimated that by 2030 the global number of overweight and obese people may double to 3.3 billion. That would have huge implications for individuals, governments, employers, food companies and makers of pharmaceuticals.

Barry Popkin of the University of North Carolina has been pointing out for years that the nutrition transition in the world is leading us to increasingly unhealthy diets, as we eat more food, especially processed food, and exercise less. Every time you turn around you hear health practitioners reminding us to eat less and exercise more. Most people hear it, but pay no attention to it, so here we are.