Science

Harvard researchers studied more than 25,000 American kids — and made a worrisome prediction about what they'll be like by age 35

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John Vizcaino/Reuters
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  • A new Harvard study projects that more than 57% of today's kids will be obese by their 35th birthday.
  • Skyrocketing obesity rates around the globe are being blamed for higher cancer rates.
  • Researchers say too much screen time and bad diets are largely to blame.

 

More American kids than ever are expected to carry a heavy load into adulthood.

In a study published Thursday in the New England Journal of Medicine, researchers at Harvard's school of public health extrapolated future obesity trends based on more than 25,000 children's current heights and weights. They estimate that nearly 6 in 10 kids in the US today will be obese by age 35. 

"When we look at trends in weight gain over the past 40 years, its not too surprising that we're heading in this direction," lead study author Zachary Ward told Business Insider.

Still, the projection is quite a jump from the current obesity rate, which hovers between 35-40% for 35-year-old adults. Overall, The Centers for Disease Control and Prevention estimates that roughly 38% of American adults can be classified as obese.

Ward said that the younger kids are when they develop obesity, the harder it it is for them to become healthy adults.

Increased screen time and bad diets are two of the reasons that rates are on the rise, he said. Ward's team at Harvard is researching new ways to prevent childhood obesity, like serving healthier snacks, limiting kids' screen time, and cutting sugary drinks like juices at nursery schools. 

"Children have already gained enough excess weight in young childhood that it puts them on a trajectory that's really hard to change as they grow older," Ward said. 

The obesity epidemic has been growing around the world for decades, but rates in the US have been climbing faster than any other country. Between 2003 and 2014, obesity rates in American kids aged 2-5 actually decreased from 13.9% to 9.4%. But rates in the other age groups have remained stable or continued to rise.

"Unhealthy foods are cheaper and they're everywhere; if you go to any store, you can buy a candy bar at the checkout but not a piece of fruit," Andy Bellatti, a registered dietitian and the cofounder of Dietitians for Professional Integrity, told Business Insider earlier this year.

On Wednesday, the United States Department of Agriculture relaxed nutrition rules for school meals, so cafeterias are now allowed to serve more processed breads, fewer whole grains, and more flavored milks. They can also add more sodium to kids’ breakfasts and lunches.

Obesity is measured by comparing height and weight, a metric known as 'Body Mass Index' or BMI. A BMI score of '30' or higher is generally considered obese. (A person who is 5 feet 9 inches tall and weighs in around 203 pounds would likely be considered obese, which is a step up from 'overweight.') 

Recent research has also shown that obesity is carcinogenic: A new report in The Lancet this week blames high BMI for 3.9% of all cancer cases worldwide, or more than half a million cases. 

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Hilary Brueck
Hilary Brueck is a Health Correspondent at Business Insider, where she covers longevity and the quest to improve human aging. She also writes regularly about the complexities of diagnosing and treating cancer, the evolving landscape of GLP-1 drugs, new developments in exercise science, and expert-backed nutrition adviceIn general, she relishes any opportunity to unpack scientific discoveries or examine the latest consumer trends. Her reports have ranged from exploring how sherpas effortlessly climb into the thin air 29,029 feet above sea level to summit Mount Everest, to trudging along a Jersey shore beach with scientists fighting killer pandemic flu viruses by studying bird butts.She spoke with Dr. Anthony Fauci about his vitamin and supplement routine over a cold slice of pizza, and chatted with the world's oldest Nobel Prize winner in his basement solar lab. She also went an entire month without eating any ultra-processed foods (yes, it was time-consuming and challenging). A graduate of Columbia Journalism School and former Peace Corps Volunteer, Hilary speaks English, French, and Malagasy. Previously, Hilary reported for ABC News Radio, Fortune, Forbes, and Al Jazeera America. In her spare time, she likes to run, hike and she is also an aspiring (but very bad) surfer. If you've got a pressing health question, tip, or concern, reach out to hbrueck@jkmperu.com