Breast Cancer and Weight Gain
In a large study of more than 44,000 women, scientists from the American Cancer Society found that the more weight a woman gained over her adult life, the greater her risk of all types, stages, and grades of breast cancer.*
Numerous studies in the past have linked excess weight with rising rates of breast cancer. This study is the first to investigate the relationship between weight gain and type of breast cancer.
Women who gained more than 60 pounds after age 18 were almost twice as likely to be diagnosed with ductal-type breast cancer and 1.5 times more likely to have lobular-type breast cancer compared to women who gained 20 pounds or less.
In 1992, at the beginning of the study, the women, then ages 50 to 74, were weighed and asked what they weighed at age 18. Surveys sent in 1997, 1999, and 2001 continued to inquire about the women’s weight and health, particularly cancer diagnoses.
All Breast Cancer Types
“Weight gain was associated with increased risk at every tumor stage and grade,” reported lead investigator Heather Spencer Feigelson and colleagues of the American Cancer Society in Atlanta, Georgia.
The risk of breast cancer that had spread increased for all women who gained weight, and tripled for women who put on more than 60 pounds compared to women who managed to keep their weight gain at 20 pounds or less.
Concluded Dr. Feigelson: “These data further illustrate the relationship between adult weight and breast cancer, and the importance of maintaining a healthy body weight throughout life.”
Scientists suspect that excess body fat fuels the growth of breast cancer because fat tissue produces estrogen. The more fat tissue you have, the more estrogen there is circulating in your body. That’s a problem, explained Dr. Feigelson, because higher levels of estrogen are linked with higher risk of breast cancer.
Several studies over the last 15 years have found that the Pritikin Program of diet and exercise dramatically lowers levels of estrogen. In 1991, for example, UCLA scientists tracking postmenopausal women attending the Pritikin Longevity Center found that estrogen levels fell on average 50%.**
And recent research on postmenopausal women at the Pritikin Longevity Center found that estrogen levels fell 35 to 40%, and in a very short time, just two weeks.
Author James Barnard, PhD, UCLA, reported: “The results of this study show that when overweight/obese postmenopausal women adopt a very-low-fat, high-fiber diet consisting mainly of fruits, vegetables, and whole grains with limited amounts of animal protein, and do daily aerobic exercise, major reductions in breast cancer risk factors can be achieved in two weeks.” ***
* Cancer; Published Online: May 22, 2006 (DOI: 10.1002/cncr.21965); Print Issue Date: July 1, 2006.
** Nutrition, 1991; 7: 137.
*** Nutrition and Cancer, 2006; 55: 28.