New Study Suggests Genetics Can Predict Obesity in Childhood

A groundbreaking international study has revealed that our DNA may hold vital clues about our risk of developing obesity — even before we hit kindergarten. Using genetic data from more than five million people, researchers have developed a new polygenic risk score (PGS) that can accurately predict an individual’s likelihood of developing obesity starting from early childhood.

This discovery opens up exciting new possibilities for targeted early intervention, offering hope in the fight against a growing global health crisis.

Unlocking obesity risk through DNA

Led by researchers from the University of Copenhagen and the University of Bristol, the study has created the most advanced genetic tool to date for predicting obesity. The polygenic risk score, built on the world’s largest and most diverse genetic dataset, assesses thousands of genetic variations that collectively influence a person’s body mass index (BMI) and appetite regulation.

Assistant Professor Roelof Smit, lead author of the study published in Nature Medicine, explains:

What makes the score so powerful is the consistency of associations between the genetic score and BMI before the age of five and through to adulthood — timing that starts well before other risk factors begin to take shape. Intervening at this point could theoretically make a huge impact.

The PGS predicts a person’s obesity risk with twice the accuracy of previous methods and accounts for nearly 17% of the variation in BMI, an unprecedented leap in the field of genetic research.

Why this matters

According to the World Obesity Federation, more than half of the global population is expected to be overweight or obese by 2035. While traditional treatment methods like diet, medication, and surgery exist, they are not universally available or effective, and they typically come after weight problems have developed.

This new research highlights the potential of genetics as a preventive tool rather than just a diagnostic one. By identifying children with a high genetic predisposition to obesity early on, public health efforts can shift focus from treatment to prevention.

Dr. Kaitlin Wade, co-author and Associate Professor in Epidemiology at the University of Bristol, underscores this point:

Obesity is a major public health issue, with many contributing factors including genetics, environment, and behavior. Some of these likely begin in childhood. This work offers an exciting opportunity to detect at-risk individuals earlier in life and intervene proactively.

How the polygenic risk score was built

To develop the PGS, researchers used data from:

  • GIANT Consortium, a large-scale genetics initiative focused on anthropometric traits
  • 23andMe, consumer DNA testing data
  • Children of the 90s study, longitudinal BMI data tracked from birth

This allowed scientists to link specific genetic markers with patterns in BMI from early childhood through adulthood. When tested on over half a million individuals, the new score outperformed all previous models, establishing itself as a reliable early predictor of obesity risk.

Not just genetics

One of the most important takeaways from the study is this: Genetics is not destiny.

While the PGS can signal risk, lifestyle interventions, such as healthy eating, physical activity, and behavioral support, still play a critical role in outcomes. Interestingly, the study also found that individuals with a higher genetic risk for obesity were more likely to respond positively to weight-loss interventions. However, they also tended to regain weight more quickly after interventions ended.

The future of obesity prevention?

This research represents a major leap forward in understanding the complex genetic underpinnings of obesity. By identifying high-risk individuals in early childhood, there’s a real possibility to prevent obesity before it takes root, rather than trying to reverse it after the fact.

If adopted widely, polygenic risk scores could become a key tool in pediatric medicine, guiding personalized lifestyle coaching and health education that could change the trajectory of a child’s life.

Your responses and feedback are welcome!

Source: “New genetic test predicts obesity before you start kindergarten,” ScienceDaily, 7/23/25
Source: “A new genetic test may be able to predict obesity in early childhood. What to know,” USA TODAY, 7/23/25
Source: “New genetic test predicts obesity risk in early childhood,” Contemporary Pediatrics, 7/22/25
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About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
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Presentations

Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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