Gaining 1 pound per year increases breast cancer risk

Overweight/obesity is a significant risk factor for breast cancer.1 The American Institute for Cancer Research estimates that 17% of breast cancers (this equates to 33,000 new cases per year) are due to excess weight alone, and women who are obese when diagnosed are more likely to die from breast cancer after diagnosis.2

Obese womenA study of 72,000 postmenopausal women presented at the 2010 American Association for Cancer Research annual meeting took into account body mass index (BMI) at age 20 and at their current age (55-74), and compared breast cancer risk between those who gained weight and those who did not. They found that a 5 point increase in BMI during these years doubled the likelihood of postmenopausal breast cancer compared to women whose BMI remained stable.3

Although excess weight has been consistently associated with breast cancer risk, the scientists undertook this study because previous studies investigating BMI or body weight during early adulthood were not conclusive. Rather than look simply at BMI at age 20, they looked at the change in BMI over time. Their results clearly indicate that weight gain puts women at risk for breast cancer, and confirms the importance of maintaining a healthy weight for cancer protection.

How much weight gain is risky?

Weight gain of 30 lbs. in a 5’4” woman would produce a 5 point increase. This may seem like a large amount of weight, but over thirty years, it would be a barely noticeable amount – a steady weight gain of 1 pound per year. This study suggests that even 1 pound per year is a dangerous amount of weight gain. And it turns out that this dangerous amount of weight gain is quite common - 60% of the women in the study had increased their BMI by at least 5 points since age 20.4  This tells us that most American women likely do gain this much weight during adulthood, doubling their risk of breast cancer.

Read more about breast cancer prevention.


1. Cleary MP, Grossmann ME. Minireview: Obesity and breast cancer: the estrogen connection. Endocrinology. 2009 Jun;150(6):2537-42.

2.  Abrahamson PE, Gammon MD, Lund MJ, et al. General and abdominal obesity and survival among young women with breast cancer. Cancer Epidemiol Biomarkers Prev. 2006 Oct;15(10):1871-7.

3. Sue LY, Genkinger JM, Schairer C, Ziegler RG. Body mass index (BMI), change in BMI, and postmenopausal breast cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; 2010. Abstract number 4823

4. U.S. News & World Report blog: Weight Gain Ups Breast Cancer Risk: 7 Ways to Avoid the Bulge. Deborah Kotz.

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see - May 20, 2010 11:13 AM

WHAT IF you eat right your entire life... are mostly vegan except some dairy every now and then, work out, are happy, passionate about what you do, love lentils, love to smile, sing, exercise... what if you do all that and still get breast cancer when you're 50 and then have it come back and
take you away when you have so much life to live and you're 55? What is that? Why does that happen? I find myself being the daughter of the person above and am going extra hard core Fuhrman diet but realllllly what is the point when she was perfect and now she's gone? This riddle I would looove answered.

Joel Fuhrman - May 20, 2010 11:55 AM

Sorry to hear about your tragic loss. These pre-menopausal cancers involves damage to DNA that typically occurred many years before, most often in childhood. Utilizing cruciferous greens, mushrooms, onions in liberal amounts in a nutritarian diet is our best opportunity to reverse any broken DNA that could have occurred from some early life cause. In these cases, being vegan is not enough, just reducing fat is not sufficient, you really need to fuel those biological repair mechanisms with lots of those super-foods. I am glad you are on board to really protect yourself with nutritional excellence.

shasha - August 7, 2010 6:22 AM

could there also be a connection with cancer and the type of foods that these women were eating? they may have been consuming alot of carcinogenic foods and the mere fact that these women put up to 30lb of weight on (spread out over time or not) suggests that their diet may not have been entirely healthy?

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