Obesity has long been classified as a global epidemic — and new data published in The Lancet journal spotlights how much worse it could get.

A team of researchers found that in 2021, one billion men and 1.11 billion women over 25 years of age worldwide qualified as overweight or obese — twice as many as in 1990.

In 2021, more than half of the world’s overweight and obese adults lived in eight countries: China (402 million), India (180 million), the U.S. (172 million), Brazil (88 million), Russia (71 million), Mexico (58 million), Indonesia (52 million), and Egypt (41 million), according to a press release.

If the increase continues at this same pace, the study projects that more than half (57.4%) of men and 60.3% of women will be overweight or obese by 2050.

In 2021, one billion men and 1.11 billion women over 25 years of age worldwide qualified as overweight or obese — twice as many as in 1990.

The three countries expected to have the highest rates of overweight or obesity by 2050 are China (627 million people), India (450 million) and the U.S. (214 million).

The study also found that by 2050, nearly one-quarter of obese adults will be 65 or older.

The researchers analyzed data from the Global Burden of Diseases, Injuries, and Risk Factors Study, spanning 204 countries and territories.

“The unprecedented global epidemic of overweight and obesity is a profound tragedy and a monumental societal failure,” said lead author Professor Emmanuela Gakidou from the Institute for Health Metrics and Evaluation (IHME), University of Washington, in the release.

“Governments and the public health community can use our country-specific estimates on the stage, timing and speed of current and forecasted transitions in weight to identify priority populations experiencing the greatest burdens of obesity who require immediate intervention and treatment, and those that remain predominantly overweight and should be primarily targeted with prevention strategies.”

The three countries expected to have the highest rates of overweight or obesity by 2050 are China (627 million people), India (450 million) and the U.S. (214 million).

Another finding was that “more recent generations are gaining weight faster than previous ones and obesity is occurring earlier.”

This increases the risk of younger people developing obesity-related conditions like type 2 diabetes, high blood pressure, cardiovascular diseases and multiple cancers.

“The world has two choices: Act aggressively now or pay an unfathomable price later.”

There were some limitations to the study, the researchers acknowledged.

“Predictions are constrained by the quantity and quality of past data as well as systemic biases from self-reported data, which are likely to remain despite attempts to correct for bias,” they wrote.   

They also noted that the definition of overweight and obesity is based on BMI (body mass index), “which does not account for variations in body structure across ethnic groups and subpopulations.”

The study also did not take into account the effects of GLP-1 anti-obesity medications and other interventions.

If cases rise to the study’s projections by 2050, a doctor warned that “obesity-related diseases will cripple healthcare systems worldwide.”

Brett Osborn, a Florida neurosurgeon and longevity expert at Senolytix, called out obesity as the “single greatest modifiable threat to longevity, economic stability and national security.”

“Yet, instead of confronting the problem head-on, our culture continues to coddle bad habits, normalize obesity and abandon personal responsibility,” he said in a statement to Fox News Digital.

“This crisis is not about food deserts genetics or corporate greed — it’s about choices. And we are making the wrong ones.”

The obesity crisis can be linked to sedentary lifestyles, ultraprocessed foods and an “entitlement mentality that demands a pill for every problem,” according to Osborn.

The obesity crisis can be linked to sedentary lifestyles, ultraprocessed foods and an “entitlement mentality that demands a pill for every problem,” according to one doctor.

“The reality is simple: Obesity is caused by caloric surplus and a lack of movement,” he said. “When you consistently eat more calories than you burn, you gain weight. Period.”

If cases rise to the study’s projections by 2050, Osborn warned that “obesity-related diseases will cripple healthcare systems worldwide.”

“The recent Lancet study projects over 1.3 billion global diabetes cases and more than two million obesity-driven cancers annually,” he said. “Cardiovascular disease will double in prevalence across multiple regions, and the economic burden will exceed $4 trillion per year. This is unsustainable.”

“Our healthcare system was never designed to support a world where over half the population has a preventable, self-inflicted disease.”

“The time to fight obesity — relentlessly and unapologetically — is now.”

The fight against obesity isn’t about aesthetics, Osborn said — “nor is this a personal affront to overweight or categorically obese people. This is about survival.”

“The world has two choices: Act aggressively now or pay an unfathomable price later,” he went on.

“The time to fight obesity — relentlessly and unapologetically — is now.”