One in five people worldwide will be obese by 2025

Obesity is a growing problem in the United States and around the world. In fact, a new study says that one-fifth of adults worldwide could be obese by 2025.

“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 author, Majid Ezzati, professor at Imperial College London’s School of Public Health in England, in a news release.

According to the study, recently published in The Lancet, the number of obese people in the world increased from 105 million in 1975 to 641 million in 2014. In addition, obesity rates increased from 3 to 11 percent among men and from 6 to 15 percent among women.

High-income, English-speaking countries such as Australia, Canada, Ireland, New Zealand, the United Kingdom and the United States account for more than a quarter of the world’s severely obese. High obesity rates are also found in the Middle East and North Africa.

Here in the U.S., one in four men and one in five women are severely obese. The study suggests those rates will increase dramatically by 2025, with 43 percent of women and 45 percent of men expected to be considered obese in the U.S.

Overweight is defined as having a body mass index (BMI) between 25 and 29.9, according to the Centers for Disease Control and Prevention (CDC). BMI is calculated by comparing a person’s weight to their height. A BMI of 30 or higher is considered obese.

According to the CDC, two-thirds of Americans are currently considered overweight or obese. These individuals are at a higher risk of developing diabetes, cardiovascular disease, hypertension, certain cancers, sleep apnea and other health conditions. The annual medical costs in the U.S. for obesity-related conditions are estimated to be $147 billion, according to the CDC.

Dr. Allen Mikhail, a bariatric surgeon at Advocate Good Samaritan Hospital in Downers Grove, Ill., says that although the equation is straightforward, obesity can be complex, as multiple factors play into it such as biological, genetic, behavioral, social, cultural and environmental influences.

“In developing countries, social norms regarding food and activity are changing. Like in the United States, instead of eating fresh foods from farms and fish from natural sources, people in developing countries are eating more processed foods and fast foods imported from Western nations,” says Dr. Mikhail. “These foods are high in sugar and saturated fats. In addition, as these nations become wealthier, people are using more technology, such as cars and computers, which results in a sedentary lifestyle.”

Dr. Mikhail describes obesity as a chronic disease that can negatively affect several systems in the body.

“Many people do not know the damaging consequences of obesity and the associated comorbidity tsunami that can lead to increasing rates of cardiovascular disease, Type 2 diabetes, stroke and some types of cancer,” he says.

Moving forward from a global standpoint, the study suggests changes to government policy to make healthy foods more accessible, while decreasing the availability of unhealthy items.

“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,” said Ezzati in a news release.