Americans got ‘fatter’ overnight without gaining a single pound thanks to new definition

If you're American, there's a chance you just became 'obese' overnight without actually gaining any weight - yes, really.

As per a Centres for Disease Control and Prevention 2024 report, more than 2 in 5 US adults are classified as obese, and that number could be set to skyrocket following new health guidance.

This is because the criteria for diagnosing the condition is changing, meaning even if you weren't classed as having the health concern previously, the new guidelines mean you could now fall into that category.

The World Health Organisation describes obesity as a 'chronic complex disease defined by excessive fat deposits that can impair health'.

Many adults with obesity also have other serious chronic diseases, including diabetes and heart disease, as a result.

As per the Independent, doctors in Massachusetts said last week that the definition of obesity should be expanded beyond a simple body mass index (BMI) test, to instead include how fat is distributed across the body.

A new definition of obesity in the US means the number of people affected has jumped from 40% to 70% (Getty Stock Image)

The BMI test has long caused debate over whether it's the most effective way to measure obesity, mainly because it doesn't take into account factors like muscle mass, age, and sex.

Essentially, it doesn't distinguish fat from fat-free mass, such as muscle and bone and other bodily tissue.

So, someone with lots of muscle could wrongly be considered obese, simply because their body weighs more.

The criticisms prompted researchers to establish a new framework, which takes into account not only BMI, but also other anthropomorphic measures such as waist circumference, waist-to-hip ratio, and waist-to-height ratio.

Under the new framework, a person is classified as having obesity if they have a high BMI plus at least one elevated anthropometric measure.

Putting their new method to the test, researchers tried it out on a group of more than 300,000 patients - and the results were quite shocking, as seen published in JAMA Network Open.

They discovered that by using this new framework, the number of obese people in the US made a huge leap from 40 percent to 70 percent.

That's right - if this study is anything to go by, 70% of the US is technically considered obese.

BMI has long been criticised for how accurate it is and the new framework takes additional factors into account (Getty Stock Image)

The doctors involved believe that this statistic reflects reality across the American population, meaning that a shocking one in four people would be considered obese.

Researchers said the sharp rise was even more pronounced among older adults and those newly added individuals on the list also had a higher risk of adverse health outcomes.

It claims that those with anthropometric-only obesity - who would not have been classified as having obesity by the traditional definition - had a higher risk of diabetes, cardiovascular disease, and mortality than people without obesity.

Co-first author Lindsay Fourman, MD, said in a statement: "With potentially 70 percent of the adult population now considered to have excess fat, we need to better understand what treatment approaches to prioritise.”

At least 76 organisations have reportedly endorsed the new guidelines, including the American Heart Association and The Obesity Society.

Senior author Steven Grinspoon, MD, added: "We have always recognised the limitations of BMI as a single marker for obesity because it doesn't take into account body fat distribution.

“Seeing an increased risk of cardiovascular disease and diabetes in this new group of people with obesity, who were not considered to have obesity before, brings up interesting questions about obesity medications and other therapeutics."