(Manan Vatsyayana/AFP/Getty Images)

New obesity statistics are out for the United States, and they show that nearly two-thirds of adults are at an unhealthy weight.

An analysis published in JAMA Internal Medicine on Monday found that 75 percent of men and 67 percent of women ages 25 and older are now overweight or obese. That's a startling shift from 20 years ago when 63 percent of men and 55 percent of women were overweight or obese and a depressing sign that campaigns to get Americans to eat healthier and exercise more may be failing.

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Based on information from the National Health and Nutrition Examination Survey, which is conducted by the Centers for Disease Control and Prevention, 67.6 million Americans were obese and 65.2 million overweight as of 2012. The CDC defines obese as having a body mass index of 30 or higher, and overweight as a body mass index of between 25 and 29.9.

This marks the first time that Americans who are obese outnumber those who are overweight.

Stopping Americans' propensity to supersize meals and lead sedentary lifestyles has become a national priority in recent decades with the launch of efforts like Michelle Obama's "Let's Move!" program aimed at children, state-funded interventions that have nutritionists going door-to-door to educate people about proper eating habits, and the Food and Drug Administration's move last week to ban transfats from the food supply.

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Researcher Lin Yang from the Washington University School of Medicine, in a statement accompanying the research letter, called the data a "wake-up call" for more aggressive policies and practices to fight obesity.

"An effort that spans multiple sectors must be made to stop or reverse this trend that is compromising and shortening the lives of many," Yang said.

Yang said in an interview that there are many reasons driving the trend but “the biggest reason is how modern society has changed with technological development.”

“This has changed the dynamics of our lifestyle and how we travel to places, how we do our housework, what we do for work. We have more and more seating-based occupations, for example,” she said.

Yang, a post-doc researcher, said that the biggest increase between the most recent data and 20 years ago is an increase in the most severe obesity among non-Hispanic black women which jumped from 8 percent to 17 percent.

She said there seemed to be no difference between the rising trend of obesity among younger adults vs. older adults.

Read more:

Special report -- HUMAN UPGRADE:

Part I: Tech titans' latest project -- defy death: For centuries explorers have searched the earth for the fountain of youth. Today's billionaires think they can create it, using technology and data.

Part II: The revolution will be digitized: Spearheaded by the flood of wearable devices, a movement to quantify consumers' lifestyles is evolving into big business with immense health and privacy ramifications.

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