Obesity
The relation of body mass index and gynecomastia has long been studied. Breast enlargement due to deposition of fat stored is now termed as pseudo gynecomastia. However, obesity has also been shown to cause true gynecomastia by interfering with the aromatase mechanism. Aromatase stimulation causes an increased synthesis of estrogen, which influences proliferation of glandular tissue in the breasts. Alteration in glucose metabolism is another way obesity causes gynecomastia.