Weight loss amount is more important than diet type in reversing obesity-cancer link
Researchers examined whether weight loss via four different diets was linked to reduced tumor growth in laboratory models of breast cancer.
In the study, researchers with the UNC Lineberger Comprehensive Cancer Center examined whether weight loss via four different diets was linked to reduced tumor growth in laboratory models of breast cancer. While tumor size did not differ between obese mice and obese mice that returned to a normal weight on a low-fat diet, they did find that obese mice that lost significant amounts of weight on three calorie-restricted diets had smaller tumors.
“Based on our results, it appears that the degree of calorie restriction, and hence the amount of weight lost, matters more than the specific dietary changes used to generate the weight loss,” said Laura Bowers, PhD, a postdoctoral fellow in the UNC Lineberger Cancer Control Education Program. “Our findings are too preliminary to make any kind of recommendation for people. The overall message is that the breast cancer-promoting effects of chronic obesity may not be easily reversible with moderate weight loss, but more severe weight loss diets may be effective regardless of whether carbohydrate or fat is restricted.”
Weight loss surgery beats diet at inhibiting breast cancer
Weight loss surgery was more effective than a low-fat diet at reversing the cancer-promoting effects of chronic obesity in mice, report UNC Lineberger Comprehensive Cancer Center researchers.
“Our basic finding was that surgical weight loss in obese mice was able to inhibit mammary tumor growth in a mouse model of basal-like breast cancer, while weight loss induced by a low fat, low calorie diet was not,” said Emily Rossi, the paper’s first author and a pre-doctoral trainee with the UNC Lineberger Cancer Control and Education Program.
“Data from human studies has suggested that there is something mechanistically different about bariatric surgery, relative to diet-induced weight loss, that makes the surgery more effective at preventing or controlling breast cancer,” Hursting said. “Now that we have (for the first time) replicated this surgery versus diet effect in an experimental model of breast cancer, we have the opportunity to determine the molecular and metabolic factors that are responsible for the protective effects of the surgery.”