Obese Classification Outweighs Those Who Are Underweight

By ACSH Staff — Apr 04, 2016
A new report in the The Lancet suggests that individuals are more likely to be classified as obese than underweight, indicating that the world's population as a whole is getting heavier. But while these findings are grim, it's an important to recognize that the main metric -- body mass index -- should be interpreted with caution.
shutterstock_360574637 BMI via Shutterstock

A new report published in The Lancet suggests that individuals are more likely to be classified as obese than underweight.

The findings are drawn from over four decades of national and international data, which used body mass index (BMI) to classify adults ages 18 and older. This data is particularly disturbing because it shows that worldwide, populations are getting heavier. And even the most poverty-stricken areas are not able to offset the morbidly-obese populations seen in western countries, as they’ve done in the past.

"Over the past 40 years, we have changed from a world in which underweight prevalence was more than double that of obesity, to one in which more people are obese than underweight," said the study's senior author Dr. Majid Ezzati.

"If present trends continue, not only will the world not meet the obesity target of halting the rise in the prevalence of obesity at its 2010 level by 2025," Dr. Ezzati added, "but more women will be severely obese than underweight by 2025."

Specifically, the analysis showed that the number of those with a BMI over 30 -- which is the benchmark for an obese classification -- increased five-fold between 1975 and 2014. Men increased from 3.2 percent globally to 10.8 percent, while women jumped from 6.4 to 15 percent.

"To avoid an epidemic of severe obesity," Dr. Ezzati continued, "new policies that can slow down and stop the worldwide increase in body weight must be implemented quickly and rigorously evaluated, including smart food policies and improved health care training."

Obesity is one of the leading modifiable risk factors associated with noncommunicable diseases that include heart disease, stroke, cancer and chronic respiratory diseases. All of which, according to the World Health Organization "are the leading causes of mortality in the world."

But while these findings seem grim, it is important to point out that BMI is an imperfect measure and one should exercise caution when interpreting it.

According to the International Journal of Obesity, BMI has "various deficiencies as a measure of overweight and obesity" particularly because it is based on self-reported height and weight. Studies show that, as a whole, individuals tends to grossly under-report weight while the opposite is true for height. Most people tend to exaggerate their true stature.

This means that aggregated BMI levels based on self-report height and weight are likely not an accurate representation of the population as a whole. Rather, it's possible that true global BMI levels are much greater than the levels reported in The Lancet study.

What's even more interesting, however, is that BMI is not necessarily linked to weight --and therefore health-status -- at all. We here at the American Council have written extensively on the issues associated with BMI, as well as in recent months.

So what is it that we can truly garner from this newest data?

Dr. George Smith, professor of clinical epidemiology at the University of Bristol, sums it up perfectly in his editorial with The Lancet, calling the study findings "striking" and representative of "a fatter, healthier but more unequal world."