I read an interesting article on CNN Health that discussed how young adults who are obese have a lower risk of breast cancer before menopause. This is compared to other young adults who are the same age and have a normal weight. However, after menopause, they have an increased risk of breast cancer because of their obesity. This is very contradictory and has some interesting implications.
These researchers do not want to promote the message that obesity is okay. One reason they speculate for the lower risk before menopause is that these women do not ovulate as much due to their large body size. This disruption lowers certain hormone levels. This is one explanation for the decrease risk in breast cancer in obese women. However, after further research, the researchers ruled out this possibility.
Currently, they are in the process of finding out the mechanism as to why obese women are less likely to get breast cancer before menopause.