Obesity and diabetes: the slow-motion disaster Keynote address at the 47th meeting of the National Academy of Medicine
Dr Margaret Chan
Director-General of the World Health Organization
Members of the National Academy of Medicine and your distinguished guests, ladies and gentlemen,
The world has 800 million chronically hungry people, but it also has countries where more than 70% of the adult population is obese or overweight.
Until the late 20th century, dietary issues in developing countries focused on the health consequences of undernutrition, especially stunting and wasting in children and anaemia in women of child-bearing age.
That situation has changed dramatically. In just a few decades, the world has moved from a nutrition profile in which the prevalence of underweight was more than double that of obesity, to the current situation in which more people worldwide are obese than underweight.
Once considered the companions of affluent societies, obesity and overweight are now on the rise in low- and middle-income countries, particularly in urban areas, where the increase is fastest.
Since 1980, WHO estimates that the worldwide prevalence of obesity has more than doubled, with significant increases seen in every region. In sub-Saharan Africa, the number of overweight children grew from 4 million in 1990 to 10 million in 2012.
Though adiposity is increasing everywhere, the epidemiology differs according to the age of the obesity epidemic. In North American and Europe, the prevalence of obesity is highest among lower-income groups, who often live in urban areas blighted by food deserts and littered with fast-food outlets.
In countries more recently affected by the obesity epidemic, as in the Asia-Pacific region, obesity is seen first in wealthy urban residents, and then later in impoverished rural areas and urban slums.
This shift to population-wide obesity is occurring with terrifying speed. In Mexico City, adult obesity increased from 16% of the city’s population in 2000 to 26% in 2012. By that year, 35% of the city’s children, aged 5 to 11 years, were obese or overweight. For the country as a whole, seven out of ten Mexicans are now overweight, with a third of them clinically obese.
In India, the prevalence of overweight increased from 9.7% near the turn of the century to nearly 20% in studies reported after 2010. For children and adolescents, these studies show that obesity and overweight are rapidly increasing, not just in the higher income groups but also in the rural poor, where undernutrition and underweight remain major health concerns.
Many other rapidly developing countries show a similar pattern. Obesity and undernutrition can occur side-by-side in the same country, the same community, even the same household.
In China, as decades of food scarcity were replaced by abundance, the prevalence of obesity and overweight more than doubled during the last decades of the 20th century, moving from famine to feasting in less than a generation.
In 2012, China’s Minister of Health estimated that as many as 300 million Chinese were obese in a population of 1.2 billion. China, with the world’s second largest economy, now vies with the US as the nation with the largest number of overweight citizens.
Earlier this year, the Lancet published a pooled analysis of trends in adult body-mass index in 200 countries from 1975 to 2014. In 1974, the study estimated that 105 million adults worldwide were obese. By 2014, the number had grown to 640 million, more than a six-fold increase. This is more than half a billion people.
The analysis reached a stunning overarching conclusion. If post-2000 trends continue, the probability of reaching the global obesity target, set by WHO Member States, is “virtually zero”.
The target itself is comparatively modest: by 2025, to hold the rise in the prevalence of obesity to its 2010 level. This means, basically, to keep a bad situation from getting much worse.
And it is a bad situation, a slow-motion disaster.
Population-wide increases in body weight are the warning signal that big trouble is on its way. It takes time, but trouble eventually arrives as a wave of lifestyle-related chronic diseases.
Cardiovascular diseases are now the leading killers worldwide. In the developing world, heart attacks tend to kill abruptly, with no lingering burden on the health system.
For cancer, the most devastating diagnosis in most cultures, 70% of patients in resource-constrained settings are diagnosed so late that pain relief is the only treatment option. No radiotherapy. No chemotherapy. No surgery. No advanced treatments costing around $150,000 per patient per year.
Obesity contributes to the risk for cardiovascular diseases and some cancers. But the role of adiposity as an independent risk factor is strongest for diabetes. Moreover, diabetes with its costly complications, including blindness, limb amputations, and the need for dialysis, can place an extraordinary long-term burden on health budgets and household finances.
In rural parts of some Asia-Pacific countries, a diabetic can spend more than a third of total household income on the costs of care. In several countries, the costs of caring for diabetes alone can absorb 20% of the entire health budget.
The International Diabetes Federation estimates that the cost of caring for diabetes worldwide was at least $673 billion in 2015.
With these trends as a background, I want to make two points.
First, despite multiple efforts on multiple fronts, no country in the world has managed to turn its obesity epidemic around in all age groups.
Second, these trends ask us to think about what progress in the 21st century really means.
Economic growth and modernization, historically associated with better health outcomes, are actually opening wide the entry point for the globalized marketing of unhealthy foods and beverages and the switch from active to sedentary lifestyles.
For the first time in history, rapidly growing prosperity is making many previously poor people sick. This is happening in countries with few resources and health system capacities to respond. If current trends continue, a costly disease like diabetes can devour the gains of economic development.
Ladies and gentlemen,
Diabetes is one of the biggest global health crises of the 21st century.
WHO estimates that the number of adults living with diabetes has almost quadrupled since 1980, moving from 108 million in 1980 to 422 million in 2014. More than half of these people are unaware of their disease status and even more receive no treatment.
The global prevalence of diabetes in the adult population has also increased, nearly doubling from 4.7% in 1980 to 8.5% in 2014.
No longer a disease associated with affluence, diabetes is on the rise nearly everywhere. Like population-wide obesity, its precursor, diabetes is increasing most markedly in the cities of low- and middle-income countries.
Most people are affected by type 2 diabetes, once known as adult-onset diabetes, but no longer, as so many adolescents and children are now affected.
Each year, diabetes causes around 1.5 million deaths. High blood glucose contributes to an additional 2.2 million deaths, largely by increasing the risk of cardiovascular disease. That means 3.7 million yearly deaths related to high glucose levels. Of these deaths, 43% occur prematurely, before the age of 70.
The Asia-Pacific region is generally considered the epicentre of the diabetes crisis. In these countries, people develop the disease earlier, get sicker, and die sooner than their counterparts in wealthier countries.
Some researchers are investigating whether a genetic predisposition may be at work. Others are looking for factors in the environment that could amplify a genetic risk or operate on their own to explain this unique epidemiological pattern.
Evidence is mounting that bodies programmed during gestation and early childhood to survive on low energy intake are metabolically challenged when confronted with even modest increases in calorie intake.
Some researchers believe this may be one reason why people in India and China develop diabetes about a decade earlier than people of European origin and can do so following only a small weight gain.
In some of Asia’s most populous countries, a generation that grew up in rural poverty, with too little to eat and jobs involving hard manual labour, now lives in urban high-rise apartments, with sedentary jobs, low-cost cars, and food environments loaded with cheap and convenient calories.
Partly as a result of these changes, millions of people lifted out of poverty to join the booming middle class now find themselves trapped in the misery of diabetes and all its costly complications.
According to 2015 statistics published by the International Diabetes Federation, India has nearly 70 million adults living with diabetes, with one million deaths estimated for that year alone. With the prevalence of overweight at nearly 20%, the situation is certain to get worse.
The most alarming diabetes news comes from China.
In 2013, the Journal of the American Medical Association published a report by Chinese researchers on the prevalence and control of diabetes in their country.
Based on the findings of a large national survey, the authors estimated that China has 114 million adults living with diabetes, representing a prevalence in the adult Chinese population of nearly 12%. Less than a third of those surveyed were aware of their condition and only a quarter reported receiving treatment.
In its most shocking finding, the study estimated that nearly half of the entire adult Chinese population has pre-diabetes, amounting to an additional 493 million people at risk of this debilitating disease, with all its costly complications.
Think about what this means for the world’s second largest economy.
Looking for an explanation, the authors suggested that modernization and rising incomes were propelling rapid lifestyle changes, including a shift from traditionally healthy diets to westernized diets.
Widespread media coverage of the alarming report prompted a Chinese newspaper to run a cartoon, showing a patient with his doctor.
"Is there a cure for diabetes?" asks the anxious patient. "Yes," says the doctor. "Poverty."
Ladies and gentlemen,
Diabetes can be successfully managed, especially when detected early. WHO has international guidelines for doing so, including insulin and blood-glucose lowering drugs on its Model list of essential medicines.
Even better, diabetes can be prevented, ideally through population-wide interventions. Changing the environment in which people make their lifestyle choices requires extraordinary government commitment, courage, and persistence.
The Lancet 2015 obesity series points the finger at the international food system as the principal driver of the global obesity epidemic.
In addition, obesogenic environments are shaped by international trade policies, agricultural subsidies, heavy advertising, also to children, politically powerful lobbies, and money invested to distort the scientific evidence.
We have seen this most recently with a report on how the sugar industry artificially sweetened nutritionists at a prestigious university back in the 1960s to downplay the role of sugar in disease.
In the second half of the previous century, the world’s food system began to concentrate almost exclusively on increasing the production and reducing the cost of food. Food production became industrialized.
Techniques were developed to grow vegetables without soil. Confined animal feeding operations sprung up to meet the growing demand for cheap meat and dairy products.
The 2005 report of the Pew Commission on Industrial Farm Animal Production, titled “Putting meat on the table”, exposed the dire consequences of industrial meat farms for the environment, human health, animal welfare, and rural America.
The report is generally considered the most profound explanation of why factory meat production is dangerously unhealthy and unsustainable.
Unfortunately, many middle-income countries with a booming middle class, like Brazil, China, and India, have adopted factory farming models from North America and Europe to meet the growing consumer demand for meat that nearly always follows new prosperity.
For example, China now has single mega-factory farms capable of producing more than a million pigs each year.
While consolidating meat production undoubtedly improves food safety, it is environmentally unsustainable.
And it comes at a time when WHO and other health agencies are advising populations to reduce meat consumption as a strategy for preventing noncommunicable diseases.
For all these reasons, much food production is now divorced from its primary purpose of providing the nutrients that sustain human life in good health.
Following a series of high-profile mergers and acquisitions, agribusiness is now a global industrial complex operated by just a handful of large multinational corporations that control the food chain, from seeds, feed, and chemicals, to production, processing, marketing, and distribution.
The dominance and power of this industrial complex are immense. They help explain why highly processed junk food is becoming the new global food staple.
They are crowding out an ancient food system, maintained by smallholder and backyard farmers, that has long fed millions of people in Africa and Asia. Municipal authorities now find it cheaper to import processed foods than to gather fresh produce from the hinterlands.
The food industry resists interference from a health agency like WHO, and it has the power to do so.
In a world full of so many uncertainties, economic, trade, and industry considerations can dominate national and international agendas and override the best interests of public health.
But we are seeing some progress.
In 2013, the Codex Alimentarius Commission mandated the disclosure of total sugars, sodium, and saturated fat in its international guidelines for food labelling.
One of the strongest recommendations of the WHO Commission on Ending Childhood Obesity calls on governments to implement an effective tax on sugar-sweetened beverages. WHO recommends that, to be effective, a tax should increase the price by at least 20%.
The Commission's report further urged governments to accept their responsibility to protect children, including a responsibility to take action without considering the impact on producers of unhealthy foods and beverages.
The oft-heard argument that lifestyle behaviours are a matter of personal choice does not apply to children. Obesity in children is society’s fault, not theirs.
Last year, WHO issued new guidelines for free sugars, recommending that they account for less than 10% of total energy intake. A further reduction to less than 5% of total energy was recommended to bring additional health benefits.
That guideline prompted South Africa, with its obesity epidemic, and the Philippines, where 97% of six-year-olds have tooth decay, to seek WHO guidance in drafting appropriate legislation to tax sugar-sweetened beverages.
These countries join US cities, like Berkeley and Philadelphia, which are already taxing soda. Next month, three more cities will vote on a proposed tax.
Giving consumers transparent and useful information also helps. I commend US authorities for their efforts to include in the country’s “nutrition facts” labels, not just total sugars, but also added sugars.
I wish you every success in getting these changes introduced.
Ladies and gentlemen,
I have a final comment.
When crafting preventive strategies, government officials must recognize that the widespread occurrence of obesity and diabetes throughout a population is not a failure of individual willpower to resist fats and sweets or exercise more.
It is a failure of political will to take on powerful economic operators, like the food and soda industries.
If governments understand this duty, the fight against obesity and diabetes can be won. The interests of the public must be prioritized over those of corporations.