The effects of estrogen are harmful when unopposed. The addition of natural progesterone provides balance to estrogen. Estrogen promotes cell proliferation, and is a leading cause of breast cancer when not balanced by progesterone. Estrogen causes fat cells to grow - fat cells make more estrogen... and the estrogen makes more fat cells! See where I'm going? So, the more body fat someone has, the more estrogen dominant that person becomes. This contributes to many diseases and health risks that can be reversed by finding hormonal balance. Weight loss can become a terrible struggle of self deprivation and excessive exercise, with little to no results. This is because your hormones are holding on to body fat and fluid.