In 2010, humanity passed an important milestone. According to the Global Burden of Disease Study, published in the British medical journal The Lancet, obesity became a bigger public-health problem than hunger.
Today, according to the latest edition of the study, more than 2.1 billion people—nearly 30% of the global population—are overweight or obese. That is nearly two and a half times the number of adults and children who are undernourished. Obesity is responsible for about 5% of deaths worldwide.
This crisis is not just a pressing health concern; it is also a threat to the global economy. The total economic impact of obesity is about $2 trillion a year, or 2.8% of world GDP—roughly equivalent to the economic damage caused by smoking or armed violence, war, and terrorism, according to new research by the McKinsey Global Institute (MGI).
And the problem is likely to worsen. If the current trend continues, almost half of the world’s adult population will be overweight or obese by 2030. As World Health Organization (WHO) Director-General Margaret Chan has noted, “Not one single country has managed to turn around its obesity epidemic in all age groups.” According to the OECD, from 2000 to 2013, the prevalence of obesity increased by at least 0.5% per year in 130 of the 196 countries for which data were collected.
This global epidemic is not confined to advanced countries. As emerging economies climb out of poverty, their citizens are becoming fatter. More than 60% of the world’s obese people live in developing countries, where rapid industrialization and urbanization are boosting incomes and therefore calorie intake. In India and China, the prevalence of obesity in cities is 3-4 times the rate in rural areas.
Indeed, the evidence suggests that developing countries are especially vulnerable to the epidemic. Obesity rates tend to explode in countries where food was once scarce and suddenly becomes plentiful. In the mid-twentieth century, for example, a boom in phosphate mining transformed the Micronesian island state of Nauru from a land of food shortages and starvation to the world’s leader in obesity and type-2 diabetes. In 2005, according to the WHO, 94% of men and 93% of women in Nauru were overweight, and more than 70% of the population was obese.
To make matters worse, in countries with limited public-health services, the cost of health care falls directly on the afflicted households. As a result, obesity can lock in poverty and perpetuate inequality.
Through a review of 500 intervention trials around the world, MGI has identified 74 potential interventions that could be used to address obesity. These include subsidized school meals, urban design that encourages walking, better nutritional labeling, restrictions on the advertising of high-calorie food and drinks, and fiscal measures.
Education concerning the risks of obesity is important, as is taking personal responsibility for one’s health, fitness, and weight. But all the evidence shows that relying on knowledge about obesity and willpower is not enough to offset the evolutionary instinct to overeat. These effects are compounded by lifestyles that require little or no physical activity.
People need help, and that means changing the environmental forces shaping their decisions—by, say, reducing standard portion sizes, altering marketing practices, and designing cities and educational establishments to make it easier for people to exercise or be active.
MGI was able to collect enough data on 44 of the 74 potential interventions to develop an initial assessment of their impact if they were scaled up to a national level. If the United Kingdom, for example, were to deploy all 44 interventions, it could rein in obesity rates and help roughly 20% of its overweight and obese population return to a healthy weight within 5-10 years.
Over the long term, savings from reduced health-care spending and gains from higher productivity could outweigh the investment needed to deliver interventions. In the UK, reversing obesity trends could save the National Health Service about $1.2 billion a year.
For many countries, tackling obesity will require a national—if not global—effort. Only a coherent, sustained portfolio of initiatives, implemented on a large scale, will be effective. No single entity—government, retailers, consumer-goods companies, restaurants, employers, media organizations, educators, health-care providers, or individuals—can address obesity on its own.
We do not yet have all the answers when it comes to the best way to tackle obesity. But the rapid rise in obesity rates around the world creates a strong case for experimenting with interventions, to see what works. Today, investment in obesity research worldwide amounts to some $4 billion a year—just 0.2% of the estimated social costs of obesity. We can—and must—do more.
This article originally ran in Project Syndicate.