Study of over 600,000 people shows weight gain trajectory matters more than weight at single point in time
A major new study presented at the European Congress on Obesity (ECO 2026) in Istanbul reveals that people who gain substantial weight during adulthood face dramatically elevated risks for multiple cancer types, with men who develop obesity before age 30 experiencing a five-fold increased risk of liver cancer.
The research, conducted by Associate Professors Anton Nilsson and Tanja Stocks from Lund University’s Department of Translational Medicine in Sweden, examined weight trajectories across decades to understand how weight changes across the lifespan influence cancer development.
Sex-Specific Cancer Risks
The findings reveal striking sex differences in cancer vulnerability. Men who became obese before age 30 showed a doubled risk of pancreatic cancer and renal cell cancer, plus a 58 percent heightened risk of colon cancer compared with men who never experienced obesity.
Women who developed obesity before age 30 faced 4.5 times increased risk of endometrial cancer, a 67 percent higher risk of pancreatic cancer, a doubled risk of renal cell cancer, and a 76 percent increased risk of meningioma.
Study Design: Tracking Weight Over Decades
The analysis used the ODDS study, a pooled nationwide Swedish cohort containing weight data spanning from 1911 to 2020, with cancer follow-up through 2023. The study included 251,041 men and 378,981 women, with each participant having an average of four weight measurements between ages 17 and 60.
Steeper weight gain was associated with higher incidence of any cancer, as well as many established obesity-related cancers among both sexes.
Broader Cancer Links
The International Agency for Research on Cancer has established substantial evidence linking excess body weight to cancers of the esophagus, stomach, colorectum, liver, gallbladder, pancreas, postmenopausal breast, endometrium, ovaries, kidneys, meninges, thyroid, and multiple myeloma.
Globally, obesity affects one in eight individuals and is recognized as a leading cause of cancer.
Timing Matters: Early Intervention Critical
The research underscores that the timing of weight gain significantly impacts cancer risk. According to co-author assistant professor Tania Stocks, steeper increases in body weight between ages 17 and 60 were associated with higher incidence of several established obesity-related cancers, with differences depending on cancer site, sex, and the timing of weight gain.
The findings suggest that maintaining a healthy weight from young adulthood through middle age may be crucial for cancer prevention, and that rapid weight gain—rather than weight at a single point in time—may be a more accurate predictor of cancer risk.
Rashmi Kumari
