Gaining weight in early adulthood is significantly more dangerous than previously thought, according to a massive study from Lund University that links early-onset obesity to a sharply increased risk of premature death.
The research, which analyzed data from more than 620,000 individuals, found that people who developed obesity between the ages of 17 and 29 face a roughly 70 percent higher risk of dying early compared to those who did not become obese before age 60. While weight gain later in life also carries health risks, the study indicates the impact is disproportionately high when it begins at a younger age.
Researchers suggest that the heightened risk is likely due to the length of time the body is exposed to the biological strain of excess weight.
“One possible explanation for why people with early obesity onset are at greater risk is their longer period exposed to the biological effects of excess weight,” said Huyen Le, a doctoral student at Lund University and the study’s first author.
When obesity sets in during a person’s 20s, the metabolic system, liver, and blood vessels endure decades of additional strain compared to those who gain weight in their 50s. The study, published in the journal eClinicalMedicine, identified type 2 diabetes as the leading cause of death associated with early-onset obesity, followed by high blood pressure and cardiovascular disease.
The study noted a significant exception regarding cancer mortality in women. Unlike other obesity-related conditions, the timing of weight gain did not seem to change the level of cancer risk for women.
Researchers believe this suggests that other biological factors, such as hormonal changes associated with menopause, may play a more dominant role in female cancer risk than the total duration of obesity.
The findings are considered particularly robust because they rely on repeated, objective weight measurements taken by healthcare staff and military officials over several decades, rather than self-reported data which can be unreliable.
Tanja Stocks, Associate Professor of Epidemiology at Lund University, said the results send a clear message to decision-makers about the need to combat an “obesogenic society”—an environment that makes it difficult for individuals to maintain healthy habits.
“It’s up to policymakers to implement measures that we know are effective in combating obesity,” Stocks said, adding that the study provides further evidence that early prevention strategies are likely to have the most significant impact on public health.