Malnourishment remains a challenge in some of the world’s poorest regions, yet, if current trends continue, by 2025 more than 21 percent of the world’s women and 18 percent of men will be obese.
Moreover, some 9 percent of women and 6 percent of men will be considered severely or morbidly obese.
These percentages represent huge rises in the occurrence of obesity, which is associated with all sorts of adverse health effects, in the years since 1975.
The numbers come from the most sweeping analysis of body mass index since then, as laid out in the April edition of The Lancet.
Collectively attributed to members of the World Health Organization’s NCD Risk Factor Collaboration (NCD-RisC, the NCD standing for non-communicable disease), the study shows that global obesity counts have skyrocketed from 105 million people in 1975 to 641 million in 2014.
The researchers drew from a pooled analysis of 1,698 population-based studies, analyzing data representing more than 19 million participants from most countries of the world, according to their study report.
They found that the age-corrected proportion of obese women more than doubled over the 40 years between 1975 and 2015, from 6.4 percent of world population to 14.9 percent, while the proportion of obese men rose from men rose from 3.2 percent to 10.8 percent.
On the upside, during the same period, the world’s proportion of underweight women fell from 14.6 percent to 9.7 percent. Among men, the underweight proportion dropped from 13.8 percent to 8.8 percent.
South Asia presently has the highest numbers of underweight people, and nearly half of the world's underweight men (46.2 percent) and women (41.6 percent) live in India.
The authors conclude that, if obesity continues to trend upward at close to the current rate, the probability of meeting the WHO’s global obesity target—returning the trend to its 2010 level by 2025—“is virtually zero.”
In an accompanying opinion piece, British epidemiologist George Davey Smith, MD, MSc, points out that disparities between the world’s overweight and underweight populations are not restricted to bodyweight.
“To the poor and undernourished in low-income countries,” he writes, “the perception of international agencies concentrating on the problems of overnourishment—and potentially encouraging the shift of health care and other resources away from undernourishment—could contribute to, rather than alleviate, social suffering.”