Research

Hormonal

Postmenopausal women who lose weight (defined as a decrease of at least 5% of body weight) after having gained weight during adulthood experience a significantly reduced risk of postmenopausal breast cancer compared to women who maintain a pattern of continuous weight gain.

If you are a postmenopausal woman who has gained weight in your 30s or later, losing at least 5% of your body weight can significantly lower your risk of breast cancer. You do not need to return to your teenage weight; even a modest reduction from your current higher weight provides substantial protection compared to continuing to gain weight. Focus on achieving and maintaining this loss, as the study indicates that weight loss, regardless of when it occurred in adulthood, is beneficial.

GoodSupportsHIGH confidence
Second, loss of weight, regardless of when it was initially gained during adulthood, was associated with a lower risk of postmenopausal breast cancer compared with the typical pattern observed in this cohort of continued weight gain.
Michelle Harvie et al. · Cancer Epidemiology Biomarkers & Prevention · 2005

Why this rating

Large prospective cohort (33,660 women), long follow-up (15 years), and adjustment for multiple confounders, though reliance on self-reported historical weight introduces recall bias.

Source

Association of Gain and Loss of Weight before and after Menopause with Risk of Postmenopausal Breast Cancer in the Iowa Women's Health Study

Michelle Harvie et al. · Cancer Epidemiology Biomarkers & Prevention · 2005

DOI 10.1158/1055-9965.epi-04-0001

cohort · n=33660Cited 343×
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DOI resolved against Crossref · corpus check 2026-06-10

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