ObesityDifference Engine: Food for thought
Fresh thinking is needed to tackle America’s obesity epidemic
AN OLD friend—grossly overweight at 365lb (26 stone or 166kg) from years of indulgence and lack of exercise caused by crippling injuries from playing defensive tackle for his university football team—tripped getting out of the shower the other day, bust an ankle and lay helpless on the floor for hours before eventually managing to crawl to a telephone and call for help. It took four strapping paramedics to get him on a gurney and into hospital.
Your correspondent has had to call out the paramedics before when his obese pal has taken a tumble. Single-handed, it is impossible to lift a helpless person of well over twice one's own weight. The floppiness and sheer mass make it nigh impossible to tug and wriggle the person onto a chair, let alone get him upright.
Even without injuries, people with a BMI (body-mass index) approaching 50 (measured as kilograms of weight divided by metres of height squared) have drastically reduced mobility. Carrying that amount of bulk, they are almost always out of breath, unable to bend, put their shoes on, get out of a chair or walk unaided for more than a few paces. Climbing stairs is out of the question.
Obesity on such a scale can also induce sleep apnoea (abnormal breathing while asleep) which, in turn, leads to daytime drowsiness and befuddlement. Meanwhile, the hypoventilation that occurs while such people exert themselves allows toxic levels of carbon dioxide to build up in their blood, making an oxygen supply more or less essential. There is no fun in being truly fat.
One third of adult Americans are overweight (ie, with a BMI between 25 and 29.9) and another third are obese (a BMI of 30 or higher), according to the National Centre for Health Statistics in Toledo, Maryland. More ominously, almost a third of those under 20 years of age are overweight or obese. Today's youngsters are on track to become the first generation of Americans to have shorter life-spans (by two to five years) than their parents—as more of them suffer, earlier in their lives, from cardiovascular disease, type 2 diabetes, cancer, osteoarthritis, liver complaints and other obesity-related conditions.
Obesity is already costing America over $190 billion a year—21% of the amount spent on medical services—and is set to rise much higher. If current trends continue, about 42% of the population will be obese by 2030, reckons the American Journal of Preventive Medicine. By then, obesity will probably cost the country $550 billion a year.
Some of the best minds have wrestled with the problem. Most agree there is no one simple explanation why obesity has become an epidemic, or how best to tame it. Top of the list of likely causes, according to Carson Chow of the National Institute of Diabetes and Digestive and Kidney Diseases in Bethesda, Maryland, is the country's massive overproduction of food that got underway a generation ago.
To support farmers, the government used to pay them not to grow crops when there was an abundance and prices too low to earn a living. Then, in the 1970s, agricultural subsidies switched to encourage farmers to grow as much as they could. Meanwhile, the green revolution, along with technological improvements to farm equipment, made agribusiness more productive than ever. Inevitably, food prices plummeted.
Lower prices meant people started eating out more often. Portions increased in size as the proliferation of pizza parlours, quick-food joints and family restaurants vied for customers. “The number of calories available to the average American grew by about 1,000 a day,” Dr Chow told the New York Times recently.
On top of that, food itself has become more calorific. One particular effect of the subsidy regime was to make high-fructose corn syrup, a sweetener manufactured from maize, much cheaper. Corn syrup is used as a substitute for table sugar (sucrose), and is equally rich in calories. The result has been that the American food industry has added it to a wider selection of products than ever before.
Moreover, Richard Wrangham, a researcher at Harvard, has built up a body of evidence that the way modern food is processed (heavily cooked, and often made from finely ground ingredients) makes more of its calories available for digestion. So, even those who are not consuming more by weight are actually consuming more by calorific value.
Meanwhile, people have adopted more sedentary lifestyles. Power tools and automation have taken the grunt out of manual jobs—in the workplace as well as around the home. Among the young, outdoor sports have given ground to indoor activities, especially video games. In Britain and Japan, your correspondent used to get at least 40 minutes of involuntary exercise a day, as he trudged to bus stops and subway stations on his way to work and back. In America, he drives everywhere.
With so many factors contributing to obesity, the only way to deal with such a complex problem is to adopt a systems approach, says the Institute of Medicine (IOM) in a report on obesity prevention published on May 8th. That means coordinating what is going on in schools, what is going on in urban planning and what is going on in agriculture, because all these things are linked, says Ross Hammond, whose work at the Brookings Institute, a think-tank in Washington, DC, is featured in the IOM's report. A four-part documentary on America's obesity crisis, produced by HBO, a premium pay-TV channel, in collaboration with the IOM, aired nation-wide this past week.
What comes out of all the hand-wringing is not a revelation. Both the IOM study and its companion HBO documentary ("The Weight of the Nation") tell people what they already knew: that fast food, processed snacks, sugary breakfast cereals, soda and juices are bad for them; that fresh food costs more than junk food, which hurts the poor disproportionately; that fad diets do not work; that real weight reduction takes time; and that the best way to manage obesity is to prevent it—for once people start gaining weight, it is very hard to shed it.
The good news is that people who lose just 10% of their weight gain significant health benefits. And though it may take years, changing your eating habits for the better and increasing the amount of exercise you do really does show results. According to Dr Chow, a person who consumes 100 fewer calories a day can typically expect to lose ten pounds over the course of three years. An interactive version of Dr Chow's model can be found at bwsimulator.niddk.nih.gov.
For the seriously obese—like your correspondent's sumo-sized chum—there is always the possibility of surgery. A procedure called gastric bypass makes the stomach smaller, causing food to bypass part of the small intestine. That reduces the amount of nutrition absorbed. It is not unusual for people to lose up to half their excess weight following gastric-bypass surgery. But they will put some of that weight back on if they subsequently fail to follow a recommended eating plan and exercise regularly. And like all surgery, there are risks, including instances where patients have died from complications.
Overall, your correspondent is not as gloomy as some about America's unhealthy eating habits. As a newcomer to the country, he was singularly impressed by the wholesale way people accepted anti-smoking rules in so short a space of time. Admittedly, sin taxes had given smokers good reason to quit, and the discounts health insurers offered non-smokers provided further incentive.
Could sin taxes and insurance breaks encourage people to eat less junk food? It is hard to say. A 35% increase in the price of sugary drinks in a cafeteria at Brigham and Women's Hospital in Boston has led to a 26% drop in consumption. But given the circumstamces, that was probably exceptional. To be really effective, a sin tax on junk food would have to be punitively high. The price elasticity of foodstuffs generally suggests that, on average, prices would need to double to get a 10% reduction in consumption. Such a tax would be unjustifiably regressive, punishing precisely the people needing to be protected the most.
A better approach all round might be to adopt financial support measures similar to those that helped create junk food in the first place, so they might do the same for healthy food. Fructose, salt and trans-fats are used widely by the food industry today because they are inexpensive alternatives for healthier ingredients. The American food industry has proved itself to be the most innovative in the world. Given the will—and enough financial inducement—that industry would no doubt find healthier, more tempting alternatives, and devise ways of marketing them at prices everyone could afford. A healthier nation would thank them hugely for it.