Body size and excess weight, conventionally assessed using body mass index (BMI), are well-established risk factors for many types of cancer. However, new research to be presented at this year’s European Congress on Obesity (ECO 2025, Malaga, Spain, 11-14 May) and published in The Journal of the National Cancer Institute shows that waist circumference (WC) is a stronger risk marker than BMI for developing obesity-related cancers in men, but not women.