Overweight raises the risk of cardiovascular disease and, as researchers at a “Genetic Toxicology” conference in Vienna explained, also significantly increases the likelihood of developing various cancers. Recent studies show that genetic damage from excess weight can be partially reversed through weight loss—even after bariatric surgery.
Cancer Researcher Warns of “Obesity Pandemic”
About 50 percent of Austrians are overweight, and around 10 percent are obese (BMI ≥ 30). “In many parts of the world, we’re facing an ‘obesity pandemic,’ with no reversal in sight,” said Siegfried Knasmüller of the Cancer Research Center at MedUni Vienna.
Less well known is that rising body weight also drives up multiple cancer risks. “Today we estimate roughly 40 percent of all cancers are caused by lifestyle and diet,” Knasmüller noted. Overweight men face higher rates of pancreatic and liver cancer; overweight women see more breast and uterine cancers. Colorectal cancer climbs similarly in both sexes.
Chronic Micro-Inflammation Stresses the Body
Excess fat provokes the immune system to attack adipose tissue, triggering low-grade inflammation throughout the body. That inflammation generates DNA-damaging free radicals. When free radicals accumulate, they can damage the genetic material in any cell.
Numerous animal studies confirm that obese mice and rats develop DNA damage and tumors in multiple organs. “These animals had genetic damage in every organ. That’s a key to cancer,” Knasmüller said.
What Happens After Major Weight Loss?
Helga Stopper of the University of Würzburg led a study of severely obese patients (average BMI 51) undergoing bariatric gastric reduction. Six to twelve months after surgery—during which many lost 25–33 percent of their body weight—blood markers of DNA damage fell significantly. “Any weight loss already brings a decrease in genome damage,” Stopper told APA.Knasmüller’s team at Vienna General Hospital and MedUni Vienna ran a parallel trial, finding similar results. Patients who lost weight more rapidly showed quicker declines in genomic-damage indicators, achieving statistical significance even sooner.
New medications can help users shed up to 20 percent of body weight while on them, but long-term effects on DNA damage and cancer risk remain unproven, Stopper said. Knasmüller adds that a fiber-rich, plant-based diet—high in antioxidants—can both support weight loss and neutralize free radicals, suggesting a shift from processed foods toward whole-grain cooking may further reduce cancer risk.
