According to nutrition epidemiologist Barry Popkin, in roughly 15 years, obesity rates in Mexico among men and women went from a small proportion of each population to 65 and 71 percent, respectively. Mexico’s situation is part of a trend of increasing obesity on a global scale. Around 2.1 billion people in the world are now either obese or overweight.

Because more than half of all the world’s obese and overweight live in fewer than 20 countries—developed countries, mostly—the temptation exists to disregard obesity’s impact on many developing countries.

However, one study found that “obesity rates tripled in developing countries between 1980 and 2008,” whereas it only increased by about half that amount in developed ones.

Developing countries tend to struggle with high levels of food insecurity, though, which one might assume would lead to lower weights, not obesity. Researchers are perplexed as to how the two factors— obesity and food insecurity —can coexist and they have been searching for data that will establish correlation, causation or both.

The recently released Global Food Security Index, which just added a new obesity indicator to its model, studies the matter in detail. Its overall conclusion affirms that co-existence is possible. Despite the correlation, it remains that the relationship between obesity and food security/insecurity is still poorly understood on a global scale.

The index helps to explain the presence of obesity in highly food insecure countries by noting differences between classes. It is the wealthier classes in developing countries, which are more food secure, that have experienced the largest increases in obesity (often after switching to more Western lifestyles).

The study also points out that obesity is increasing among the poor, as well, and experts have proposed various explanations for this phenomenon.

Some maintain the poor have to rely on high-calorie, low-nutrient food, which leads to obesity. Others look to “feast-famine cycles” for answers: poor populations swing between binging and starving—a cycle that changes one’s metabolism. Still others say obesity among the poor is rising because obesity is a wealth-indicator for the poor.

Causality remains exceedingly difficult to prove, though, because many factors, such as diet, wealth and level of physical activity, can all help cause obesity. Moreover, even correlation has been hard to establish in every developing country. In fact, studies in Ghana, Trinidad and Tobago show food insecurity correlated with lower weights, but results from studies in Malaysia were more complex.

Thus, no conclusion can be drawn as to what single factor is causing obesity in developing countries. It may be that no such factor exists.

Nevertheless, researchers will continue to search for causes. Three million people die every year from health problems that obesity contributes to. Researchers know that if they can pin down the causes of obesity, it could help to save the lives of millions.

– Ryan Yanke

Sources: Global Food Security Index, Scientific American, Huffington Post, Reuters
Photo: Today Online