The World Health Organization defines overweight by an index of body fat (BMI, calculated by dividing weight in kilograms by the square of height in meters, kg/m2) equal to or more than 25, and obesity as BMI equal to or more than 30. The excessive consumption of nutrients, a sedentary lifestyle and genetic predisposition are several of the triggers of the disease.

Another factor: consumption of energy-rich fast food, tripled between 1977 and 1995, and caloric intake quadrupled during the same period.

Until now, experts have pointed to health problems and societal costs, related to increased health spending and the loss of productivity of overweight and obese people, as the main consequences of obesity.

Respect the planet: stay thin?

A recent study by the London School of Hygiene & Tropical Medicine explains other consequences of the unstoppable rise in obesity: overweight people eat more than the rest of the population and abuse the use of the car, which means obesity isn’t just a medical or productivity cost, but that it compounds the negative impact of a person on the environment.

Surprisingly, this is one of the first studies that dares to relate obesity and excess weight with an increased carbon footprint, although the cause-effect relationship is evident. “When it comes to food consumption, moving about in a heavy body is like driving around in a gas guzzler,” given that food production is a major source of greenhouse gases, explain researchers Phil Edwards and Ian Roberts in their study.

The scientists are quick with their conclusions: “we need to be doing a lot more to reverse the global trend toward fatness, and recognize it as a key factor in the battle to reduce (carbon) emissions and slow climate change”.

The calculations don’t leave any doubt: an overweight person generates about a ton of carbon dioxide emissions more per year than a thin person, so the world’s more than one billion overweight people add more than a billion tons of CO2 to the atmosphere every year.

This is an important amount, if these emissions are put into context: The Guardian points out in their review of the study that the world’s total emissions for 2004 were 27 billion tonnes, of which up to one billion is related to excess weight and obesity.

No obesity in the news: panic over swine flu

In the era of ubiquitous communication, tools like Twitter, the micro-blogging service that has transcended “geek” status, have contributed to extend the alarm around swine flu (H1N1). Information, as well as rumors, travel faster than ever, thanks to the Internet, that complements and amplifies the impact of traditional media.

It’s surprising that WHO as well as the Mexican and U.S. governments first, and the rest of the world later, put their entire population on alert in a matter of days, and that the WHO established a planetary action protocol to attack the epidemic “with risk of pandemic”.

Obesity and excess weight aren’t illnesses that you can catch on an airplane, on public transport or while attending a football game. Their social connotations are, besides, very distinct.

In several historical periods such as the Italian Renaissance, obesity was a status symbol: then, the distinguished men of the big Italian cities proudly carried excess weight, while today obesity has become a pandemic that affects the health of the poorest and least educated classes of rich countries.

WHO estimates that there are more than 1.6 billion overweight adults, 400 million of whom are obese. The organization calculates that in 2015 there will be 2.3 billion overweight people and 700 who are obese. In 2005, worldwide, 20 million children under five were overweight.

Causes of obesity and overweight status

Obesity is officially considered one of the pandemics of the 21st Century, with predictions of increases in health spending and a decrease in life expectancy that put pressure on social structures and even life expectancy in every region.

For the first time, the current youth generation has a life expectancy less than their parents in many rich countries; obesity and excess weight, along with a sedentary and unhealthy lifestyle contribute to the phenomenon.

In medical terms, the fundamental cause of obesity and excess weight is “the imbalance between calorie intake and energy expenditure”, or overeating and physical inactivity. It may be easy to detect and put into a formula but, how do we prevent a disease that is related to style of life, education, quality of food, lack of time, the spread of processed products, carbonated drinks, alcohol, fast food and industrial baked goods?

It’s easy to explain why an individual gains weight, although it’s more difficult to give a complete diagnosis that explains why the average weight of advanced societies has been increasing in a sustained manner since the eighties, especially in Anglo-Saxon countries.

The genetic causes must be considered, according to the experts, to understand the problem, although the predisposition to gain weight doesn’t explain why obesity didn’t increase among the U.S. population between the Second World War and the sixties, despite the increase in average height and weight.

In three decades, obesity has increased and the experts think it’s due to several factors:

• Sedentariness and lack of physical activity.
• Relative cost of processed food.
• Increase in marketing related to unhealthy food in the media, especially during children’s programming. In the United States, this phenomenon was increased thanks to the deregulation promoted by Reagan at the beginning of his time in office.
• Increase in number of positions of sedentary work.
• Increase in the number of families with two incomes (nuclear families where both parents work).
• Uncontrolled geographic expansion of cities, or urban sprawl (more time traveling in the car; less time to walk, cook or exercise).
• Sustained growth of fast food restaurants and processed food. In the United States, the portions of french fries at McDonald’s increased from 200 calories in 1960 to more than 600 calories currently.

Feeding oneself in contemporary society

The book Fast Food Nation: the Dark Side of the All-American Meal, that inspired the 2006 movie of the same name, examines in depth the origins and influence of fast food in the United States and the rest of the world from it’s emergence in the middle of the 20th Century and subsequent expansion, as well as the undeniable influence on its success of a social model built around the extensive use of the car and the decentralization of cities, which in North America coincided with the dismantling of public transportation systems in many cities.

Lobbying groups, including those related to the Detroit automobile industry, form a part of the story which merits more journalistic works like that of Eric Schlosser.

WHO attributes the increase in obesity worldwide- a problem discussed in the media, although never a cause of alert although it’s much more deadly and dangerous in the longterm than pandemics like swine flu- to several factors, among those highlighted:

• “A global shift in diet towards increased intake of energy-dense foods that are high in fat and sugars but low in vitamins, minerals and other micronutrients.”
• “A trend towards decreased physical activity due to the increasingly sedentary nature of many forms of work, changing modes of transportation, and increasing urbanization.”

The causes mentioned by WHO serve to reinforce the findings of Schlosser in Fast Food Nation.

A planetary problem that affects all age groups

Two North American countries, the United States and Mexico, lead the rest of the OECD countries in percentage of their population with a body mass index superior to 30, or obese citizens. Canada, the third North American country, is also situated closer to the top of the list of the 30 countries. Of the 10 members of the OECD with the highest incidence of obesity, 5 are Anglosaxon (United States -1-, United Kingdom -3-, Australia -5-, New Zealand -9- and Canada -10-).

Regardless of those hit hardest, this is an epidemic that affects all wealthy countries. In Europe, a fifth of the population is now obese, and adult obesity accounts for up to 6% of direct health costs and more than 12% of indirect costs in the form of shortened lives, decreased productivity and diminished incomes.

Worldwide, 10% of children are classified as obese. Obesity in children is of particular concern given that it can lead to more adult diseases at a young age, such as diabetes, high blood pressure and high cholesterol.

During the period between the 1980s and 1990s, the increase in overweight and obese children in developed countries rose by a magnitude of 2 to 5 times. For boys in Canada, rates increased from 11% in the ’80s to over 30% in the ’90s.

Detecting social determinants

Several studies point to the existence of class and access to education as factors that lead to being overweight and obese. The simplest studies are also the most resounding: in the United States, comparing net worth with body mass index, a 2004 study concluded that the net worth of the obese is nearly half that of those with normal body mass.

These differences have been linked to lower education levels and increased consumption of fast and processed foods among the most disadvantaged classes in the United States. Another study found that women who marry in a favorable social environment are thinner than those who marry among a lower class.

Benefits of a- successful- fight against obesity

The fight against obesity requires a sustained political commitment, as well as the collaboration of influential societal figures, both public and private: individuals, politicians, educators, family, non-profits and businesses.

In an ideal situation, individuals could:

• Eat in a healthy and frugal way.
• Reduce their intake of calories and change their consumption from saturated fats to unsaturated fats.
• Increase their consumption of fruits and vegetables, whole grains and nuts.
• Reduce their sugar intake.
• Increase their physical activitiy (at least 30 minute of regular physical activity, of moderate intensity, most days). Note: to lose weight, it can be necessary to do more exercise.

The consequences of increased responsibility over our body and the responsible alimentation of our children and adults? The reduction of our carbon footprint, the lowering of our health bills, an increased quality of life, increased self esteem, a sustained increased in productivity, an increase in wealth.

Secondary effects of a healthy diet and regular exercise at every age? Absolutely none.

It seems our social priorities are too closely related to material and economic factors and warrant a shift toward a focus on a healthier lifestyle.