Obese People Outnumber Underweight People for First Time in Human History, Study Says The historic changes in obesity are clear in these interactive graphics.

 -- Obesity has been a growing problem in the U.S. for decades and increasingly its effect is being felt globally. A new study published by the Lancet Medical Journal finds that for the first time in human history, there are more obese people than underweight people in the world.

The data -- which was pooled from studies, surveys and reports -- looked at 19.2 million men and women from 186 countries, and shows stunning changes in less than 40 years, with an increasing average body mass index in multiple countries from 1975 to 2014.

The study estimates that 10.8 percent of men and 14.9 percent of women worldwide are obese, defined by a BMI of over 30, while just 8.8 percent of men and 9.7 percent of women are underweight, defined by a BMI of under 18.5.

How Much Heavier Are People Today?

By looking at multiple studies, researchers found that globally BMI for both men and women have gone up. In 1975, men on average were found to have a BMI of 21.7 and women had a 22.1 BMI. In 2014, those figures ware 24.2 for men and 24.4 for women.

This means that the average person became 1.5 kg, or about 3.3 pounds, heaver each decade.

What Does This Mean for the Future?

The researchers speculate that if these trends continue, approximately a fifth of men and women worldwide will be obese. Additionally, an estimated 6 percent of men and 9 percent of women will be severely obese, with a BMI of over 35, putting them at risk for a host of health problems, including heart disease, diabetes and high blood pressure.

"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, but more women will be severely obese than underweight by 2025," said Professor Majid Ezzati from the School of Public Health at Imperial College London. "To avoid an epidemic of severe obesity, 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."

The Countries With the Highest, Lowest and Unchanged BMI

The tiny island nations of Polynesia and Micronesia have the highest BMI averages in the world, according to the study. In American Samoa, the average BMI for women reaches 34.8 and the average BMI for men is 32.2.

In some European and Asian countries, the average BMI has not increased. These countries -- including Singapore, Japan, Czech Republic, Belgium, France and Switzerland -- had virtually no increase in women's BMI averages.

The lowest BMI averages were found in Timor-Leste, Ethiopia and Eritrea. The lowest BMI for women was in Timor-Leste were the average BMI is 20.8 and for men the lowest BMI was found in Ethiopia with an average BMI of 20.1.

Being Underweight Is Still a Problem for Many Throughout the Globe

The researchers said people being underweight is still a huge issue globally. A quarter of women in India and Bangladesh are underweight. A fifth of men in India, Bangladesh, Timor-Leste, Afghanistan, Eritrea and Ethiopia are underweight.

Being underweight put a person at risk for multiple health problems including anemia, infertility and osteoporosis.