There are numerous risk factors for breast cancer that cannot be controlled, but also others that can be prevented by women. Being overweight or obese increases the risk of suffering from the disease and it is among the factors that can be controlled. Defined as having a body mass index (BMI) lower than 24.9, maintaining a healthy weight is particularly important after menopause. When women menstruate, the female sex hormone estrogen is produced in the ovaries but after the menopause, it is mainly produced by fatty tissue. Having more fat cells means that there is a higher production of estrogen, which can result in the development and growth of hormone-receptor-positive breast cancers. For women who suffered from breast cancer, being overweight means having a higher risk of cancer recurrence.