A new study presented at the European Congress on Obesity (ECO) in 2025 has found that adults who gain the most weight during adulthood face a significantly higher risk of developing certain obesity-related cancers. The research, led by the International Agency for Research on Cancer (IARC), analyzed data from over 300,000 participants across Europe.
The study specifically linked substantial weight gain—defined as gaining more than 10 kg (22 lbs) over a 10-year period—to a fivefold increased risk of developing cancers such as endometrial, kidney, and gallbladder cancer. The findings underscore the importance of maintaining a healthy weight throughout adulthood to reduce cancer risk.
Dr. Heinz Freisling, co-author of the study, stated: 'Our results highlight the critical window of adulthood for weight management. Even modest weight gain can significantly increase cancer risk.' The study controlled for factors such as smoking, alcohol consumption, and physical activity.
Experts note that obesity is already a known risk factor for at least 13 types of cancer, including breast, colon, and pancreatic cancer. The new research adds to the evidence that weight gain in adulthood is a particularly dangerous period for cancer development.
The World Cancer Research Fund recommends maintaining a healthy weight, being physically active, and eating a balanced diet to reduce cancer risk. The study was published in the journal BMC Medicine.
